ConcoursMustang Forums
1st Generation 1964 1/2 - 1973 - Questions & general discussions that apply to a specific year => 1970 Mustang => Topic started by: 70Mach on September 12, 2013, 05:31:50 PM
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Last night was the first time for a battery test on the electrical system before the dash goes in and the front of the car is assembled. Opened the door and the buzzer started along with the left sail panel light coming on, excellent! But the right sail panel light wasn't, hmmmm. Then, with the driver's door open I turned on the lights, blew the courtesy light fuse. All wiring harnesses that are available reproduction have been used - Metal Alloy Products brand. The convenience group harness was not replaced because I don't think it's available reproduction. But it's not hacked up and didn't see any issues with a good visual inspection before I reinstalled it. Has anybody seen this issue before? It was late when I hooked it up so didn't mess around with it too much. For one, I probably need to have the door shut and see if it still blows the courtesy light fuse when I turn the lights on. And I also need to check the bulb/circuit for the right sail panel. Although I would think if that was the problem it would just have blown the fuse right away when I opened the door. I think it's two separate issues but have not confirmed that yet. Just seeing if anyone else has had a similar issue with replacement harnesses or the Convenience Group system. Thanks!
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Okay, finally got to work on it again. I checked and didn't have the passenger's side door switch circuit completely hooked up. Once I did that, the passenger side sail panel light works. I still have the fuse issue though. With the key off (left in ignition), driver's door open, buzzer buzzing, interior lights lit up, and I turn the light switch ON it blows the courtesy light fuse which kills the interior lights and the buzzer. Then with same scenario except the driver's door closed the fuse does not blow. Any ideas? I didn't take this car apart and don't have any prior experience with this system. One thing that is bothering me is a connection that I had made when assembling the harness. Towards the center of the dash there is a blue w/red stripe wire and a black wire going into 1 connector. I plugged that into a black wire coming off one of the connectors for the lights "ON" indicator relay that is right under the buzzer. On these two connectors one is black the other is white, but they are the only ones that are 'mates'. When I unplugged that connection, opened the door, key off (key left in ignition), and turned the lights on the fuse didn't blow, the buzzer buzzed and the interior lights came on. But the light for the shift indicator wasn't lighting up (although I don't know if it was before I unplugged the connection either). I traced the blue/red wire w/ black wire connector to the transmission shift indicator light.
Also at times, when working around the buzzer and the relay, with the key out of the ignition and the driver's door open the buzzer would start buzzing slightly. If I pushed the driver's door switch in it would stop even and when I let go of the door switch it would continue to be off and occasionally would start slightly buzzing again when I touched the buzzer or relay below it. That makes me think I maybe I'm getting a back feed or maybe a poor ground somewhere?
One more thing, in the Osborn electrical manual it says there is a black/red wire going to the light in the shift indicator? My automatic shifter assembly hasn't been touched and the wire is blue/red like all other dash lights.
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Okay, finally got to work on it again. I checked and didn't have the passenger's side door switch circuit completely hooked up. Once I did that, the passenger side sail panel light works. I still have the fuse issue though. With the key off (left in ignition), driver's door open, buzzer buzzing, interior lights lit up, and I turn the light switch ON it blows the courtesy light fuse which kills the interior lights and the buzzer. Then with same scenario except the driver's door closed the fuse does not blow. Any ideas? I didn't take this car apart and don't have any prior experience with this system. One thing that is bothering me is a connection that I had made when assembling the harness. Towards the center of the dash there is a blue w/red stripe wire and a black wire going into 1 connector. I plugged that into a black wire coming off one of the connectors for the lights "ON" indicator relay that is right under the buzzer. On these two connectors one is black the other is white, but they are the only ones that are 'mates'. When I unplugged that connection, opened the door, key off (key left in ignition), and turned the lights on the fuse didn't blow, the buzzer buzzed and the interior lights came on. But the light for the shift indicator wasn't lighting up (although I don't know if it was before I unplugged the connection either). I traced the blue/red wire w/ black wire connector to the transmission shift indicator light.
I'll leave this one to the electrical guys here - its not me :(
Also at times, when working around the buzzer and the relay, with the key out of the ignition and the driver's door open the buzzer would start buzzing slightly. If I pushed the driver's door switch in it would stop even and when I let go of the door switch it would continue to be off and occasionally would start slightly buzzing again when I touched the buzzer or relay below it. That makes me think I maybe I'm getting a back feed or maybe a poor ground somewhere?
I vote for a poor ground - the most common culprit in this electrical in cars
One more thing, in the Osborn electrical manual it says there is a black/red wire going to the light in the shift indicator? My automatic shifter assembly hasn't been touched and the wire is blue/red like all other dash lights.
Possibly the color code changed earlier in the year (one of the possible reasons that particular sheet was printed), changed later or the manual was incorrect at the time the page was printed an possibly caught later. All kinds of possibilities when it comes to the Assembly Manuals
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Towards the center of the dash there is a blue w/red stripe wire and a black wire going into 1 connector. I plugged that into a black wire coming off one of the connectors for the lights "ON" indicator relay that is right under the buzzer. On these two connectors one is black the other is white, but they are the only ones that are 'mates'.
This makes no sense. Blue/red and a black wire going into a single plug/pin? or a 2 pin plug? In either case, I know of no 1970 underdash harness plug that has that configuration. Nevertheless, I believe this is the source of your problem. Typically, blue/red is a dash lamp or headlight-controlled light, and black is ground. Ford always strove to make wire colors match across plugs, and even had most mating plugs the same color.
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This might help you out. Follow wire colors until you find problem wire. The Convenience Group harness is a different animal altogether than standard harness.This was about as much of a pain to post as your wiring problem so I hope it helps!
Shelby
(http://i25.photobucket.com/albums/c76/shelbyboss302/WIRING/1970conveniencegroup_zpsf785561f.jpg) (http://s25.photobucket.com/user/shelbyboss302/media/WIRING/1970conveniencegroup_zpsf785561f.jpg.html)
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Got it!!! YES!!! The color coded diagram is what helped me figure it out. On the buzzer there are 4 terminals for two connectors, each having a black and red wire. The red wires were diagonal from each other and when reading the Osborn Electrical quickly it would appear that is the correct way. The connectors are made so they only fit one way. One of the connectors is from the original Convenience Group harness, the other is on the new main harness. The connector on the new harness had the red and black wires installed so they were diagonal from the wires on the other connector. The color coded diagram shows the red wires on one end of the buzzer and the black wires on the other. I pulled the wires out of the new harness connector, switched them around and everything works as it should! When comparing to the old main harness, it confirmed the wires were switched in the new harness connector for the buzzer. The picture is of the old harness connector.
This is the way it works now: Ignition switch OFF, key in, driver's door open - buzzer works, take the key out - buzzer stops. Then with: ignition switch OFF, key in, driver's door open, lights ON - buzzer works, take key out - buzzer continues until the light switch is turned OFF. In either situation the buzzer remains off when the door is closed.
As far as the two wires (blue/red and a black) hooked together into a single terminal, both the old harness and new harness have it. It connects to a black wire that goes to the relay below the buzzer. The other black wire coming out of that relay goes to the buzzer. The blue/red wire goes to the shift indicator bulb. The black wire goes to the headlight switch. I've attached pictures to give you a better idea of what I'm talking about. I untaped the old harness to find where those two wires go to.
I had a ground problem on the shifter housing for the indicator light. Fixed the ground problem and the light works.
Thanks for the assistance!
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Ahhh...that single pin connector! I've always wondered what it was for. It is tied to the PRNDL and marker lamp system, but I never knew what is was to be plugged in. That must be the signal to the buzzer relay that tells it that the headlights are on. BINGO!
Sorry about the confusion. I simply did not recognize that you were talking about that unusual single-pin connector. Shame on me.
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Ya, that is an odd combo going into a single connector. And probably not a connector that is used very often.
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holy crap, that was an original connector, I thought it was some aftermarket bs. the black tied to the blue/red. I don't think my car has any buzzers, so the black goes to what then, if no buzzer? Do you have a sportlamp switch and if so how is it connected? the black is powered from headlamp switch mid? powers PRNDL light and to the black wire on sportlamp switch, with the only output from sportlamp switch, the grey to lights, black with yellow is not used,
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holy crap, that was an original connector, I thought it was some aftermarket bs. the black tied to the blue/red. I don't think my car has any buzzers, so the black goes to what then, if no buzzer? Do you have a sportlamp switch and if so how is it connected? the black is powered from headlamp switch mid? powers PRNDL light and to the black wire on sportlamp switch, with the only output from sportlamp switch, the grey to lights, black with yellow is not used,
Many times, the actual PRNDL wire is blue/red. The black wire on the two (sometimes three) prong plug that plugs into the relay goes back to the turn signal connector.
Now as for the sportslamp switch, yes power comes in through the same system that gets power from the headlights and powers the PRNDL lamp and outputs a gray wire to the sportslamp via the firewall connector. I've never seen a yellow wire on that connector, however. BTW, that connector is unique to 1970 Mustangs. Similar connectors are found in Cougars and other applications, but they are not the same. Makes my life hell having to adjust other connectors to fit the 70 Mustang.
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wish I wouldn't have cut it, but at least I know it was correct. I have lights and sportlamps work with the connections u suggested. Im still blowing the fuse when turn signals actuate, but my front signal lights aren't installed and driver door light is not connected, so probably not grounded properly. Thanks for those pics, I have been waiting awhile for that particular connector pic, now just need sportlamp switch and wiring pics and that area with the dash pad removed. I still don't know why that black with yellow is there for the connecting from sportlamps switch to harness
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Is this what you're looking for?
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Is this what you're looking for?
That's the 70 sportslamp connector: rare as hen's teeth! It's a unique connector for Mustang and only that year. I've seen maybe 6 out of 100 1970 harnesses so far.
When folks want to add sportslamps to their car, I have to use a Cougar connector and modify it; even still, it doesn't have the clips to hold it into the switch.
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Yes 70mach, do you any more pics that show how/where those wires look, there is an original on eBay right now midlife, I almost bought it just because
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I just put the dash in last night, but I have my old harness and can see where they go. The old harness doesn't have the connector - a previous owner cut it off. The harness I used is the reproduction, so somebody, somewhere is making that connector. The new harness came from NPD, but I can't remember who it is made by.
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a couple pics of the harness would be good to look at, there is a black with a yellow stripe I am interested in, my sportlamp switch has this wire and the harness has it also, like they should be together, thanks for your help
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I just put the dash in last night, but I have my old harness and can see where they go. The old harness doesn't have the connector - a previous owner cut it off. The harness I used is the reproduction, so somebody, somewhere is making that connector. The new harness came from NPD, but I can't remember who it is made by.
That's likely Alloy Metal out of New York. I believe they mold their own connectors. NPD doesn't list a sportslamp variant of the 70 harness, but most 1970 harnesses can be ordered as "specials" from them.
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I don't know if these will help, in the new harness I believe there is a black and a black/yellow wire joined together into a single connecter. My old harness has them stripped and twisted together. The gray wire from the sports lamp connector and the black/yellow wire go to the green connector for the fuse block. The black wire goes through the firewall and into a bullet connector that has a blue/red wire going into the same bullet connector.
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Thanks 70mach, appreciate your help
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Glad I could help. I have one more question on the sport lamps. Do the front valance park lights shut off when the sport lamps are turned on? Got all the lights hooked up this weekend and the front park lights ( under the bumper) don't work, the new underdash main harness I installed doesn't have the black yellow wire in it! Ahhhhhhhhh! Could have swore i doubled checked all connectors to the old harness but must hsve missed that one. So it would appear that the sport lamp switch should have 3 wires going into it. The terminal on the SL switch without a wire, where the black/yellow wire should be is hot with the lights on & SL switch off. Turn the SL switch on and and it goes dead.
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The 70 wiring schematics do have three wires going to the sportslamp switch, but in practice (about 10 70 Mach 1's), I've never seen that configuration---only two wires. As previously mentioned, it was possible that there was a mid-year change from 3 to 2 wires early on in the model year.
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So on the ones you have seen with two wires, which wire is not there? The black/yellow wire? With only two wires, I wonder if the park lights were ON with or without the sport lamps being on.
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I'm thinking the black/yellow wire serves a purpose, right now I do not have mine black/yellow is not connected (taped off) and the black goes to PRND1 light, sport lamps work because the gray wire is hooked up.my turn signals keep popping the fuse, but the turn signals are installed so I wouldn't expect them to work properly. When I purchased my headlight wiring harness, the key question was build date because they went from 11 to 10 wires from firewall to lights. I think it was around 10-15-1969.
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The black/yellow wire is the power wire to the park lights under the bumper. The rest of the park light circuit is powered by a brown wire. The new underhood harness I used has the black/yellow wire going from the park lights to the firewall connector. But the new under dash harness does not have it, and my old harness does.
Ray, I think this is the way yours is working: The sport lamp switch is getting power from the PRND1 light, when you turn the SL switch on it sends power through the gray wire to light the bulbs. Since you do not have the black/yellow wire, the valance park lights are either not working or they're powered by a different source (probably the brown wire that powers the rest of the park light circuit).
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After talking to NPD, there were 4 different under dash main harnesses for 1970. The early versions had a 3 wire Sport Lamp circuit the later versions had 2 wires, the black/yellow wire was deleted. I'm guessing on the later version 2 wire Sport Lamp circuit, the front valance park lights were on the rest of the park light circuit and powered by a brown wire.
To correct my issue I need to either replace my under hood harness with a later version to match the later under dash harness. Or I need to add the black/yellow wire into the under dash harness. I would like to add the wire into this harness, but I don't know where I'll find a female terminal to add into the sport lamp connector. Any ideas?
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After talking to NPD, there were 4 different under dash main harnesses for 1970. The early versions had a 3 wire Sport Lamp circuit the later versions had 2 wires, the black/yellow wire was deleted. I'm guessing on the later version 2 wire Sport Lamp circuit, the front valance park lights were on the rest of the park light circuit and powered by a brown wire.
To correct my issue I need to either replace my under hood harness with a later version to match the later under dash harness. Or I need to add the black/yellow wire into the under dash harness. I would like to add the wire into this harness, but I don't know where I'll find a female terminal to add into the sport lamp connector. Any ideas?
The terminal pins can be found from Cougar power window assemblies as well as some of their toggle-switch convenience items. I can provide a couple female pins if you want them.
Yes, the black/yellow wire appears to have been an early version of the valence lights: I've seen that used about 10% of the 70 headlight harnesses I've refurbished. That wire is next to the two turn signal wires on the top line of the connector where the large power pin is. Most of the time, that hole is empty. the few times I've seen it on an underdash, it ties directly to the headlamp switch itself.
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Thanks for the tip on what else has them! I'll see if I can find something. I knew there had to be something else.
So the ones you saw tied directly to the headlight switch, was it with another wire into one terminal? The same one that powers the other park lights?
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When I bought my headlight harness, bill upham asked me what my build date was (10-20-69 Dearborn), does anyone know whAt the change over date was? I thought it was 10-15, but my car has the black/yellow cut on the main harness, as if it was used. Signed wtf
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Thanks for the tip on what else has them! I'll see if I can find something. I knew there had to be something else.
So the ones you saw tied directly to the headlight switch, was it with another wire into one terminal? The same one that powers the other park lights?
Only one wire, directly from the headlight switch into the firewall plug. I don't remember what happened on the engine side, as I refurbish fewer headlight harnesses than underdash. I have almost every year underdash harness memorized (yeah, I know...I'm sick).
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If your underhood harness has the black/yellow wire, I think you will need to have the black/yellow wire hooked up in the sport lamp connector. If your underhood harness doesn't have it, then I don't think the black/yellow wire will be needed in your underdash harness. If you have an original underhood harness it could be green/yellow - that's what the wiring diagrams I've seen say. Although they show green/yellow all the way to the sport lamp switch. My original underdash harness had the black/yellow wire. I'll have to look at my original underhood harness to see what color it is.
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mine is the original underdash harness, black/yellow can easily be connected and looks correct if it was connected, I will have to look at the headlight side, im sure its correct according to Mr.Bill, im not sure if it doesn't dead end at the fuse panel....isn't this black/yellow line a ground, there is a black/yellow wire grounded at the lower dash on drivers side of the instrument bezel. Im gonna connect all my lights to see if they are all working properly this weekend. My headlight harness has 10 wires, no black/yellow, so it terminates at fuse box on mine, which was built after 10-15-69, prior to that date there was 11 wires with black/yellow one. I read that on vintage mustang forums and from talking to Bill when I was ordering a replacement for the weatherbeaten original, which wasn't correct anyways, someone put a no sportlamp version on it for a time.
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Black/yellow is NOT a ground!!!! Only black wires are grounds.
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I will have to look at it again then, this is the ground I was referring to
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I just looked at both of my old harnesses, car is Metuchen 11/20/69. It has the black/yellow wire in the underdash harness. It did not have it in the underhood harness and it is a 10 wire harness. In this setup the black/yellow wire was not used in the underdash harness because all of the park lights were powered by the brown wire. (And I unknowingly just changed my car to an earlier style because I didn't take the time to compare the number of wires in my old harness to the new harness before I installed it).
When the black/yellow wire was used (11 wire underhood harness) it was the power wire to the front valance park lights only. All the other park lights were on the brown wire circuit. When the park lights or lights were turned on and the sports lamps were off the valance park lights were on. Then when the sport lamps were turned on, the front valance park lights went off.
When they went to the 10 wire underhood harness all of the park lights are on the brown wire circuit and the front valance park lights stay on when the sport lamps are turned on.
That's my thoughts on how it works. I'm wondering if they didn't change it to get all park lights on one circuit.