Wiring stumper for you guys

by bitterfitter Mon Dec 30, 2013 6:36 pm

I have found some wiring under my dash that looks factory but I have no idea what it might be for? I noticed coming down in the passenger kick panel area. It is three wires molded together; green, yellow, orange. I thought maybe something for the radio, but no. They are going no where and I put electrical tape on the ends in case one of them is live. I found the other end of them and they come from a connector of five other wires. There is a green, orange and three yellows going to this connector. I can not find where these wires come from as they are all under the dash around the headlight switch area. I am not saying they go to the headlight switch, just in that area where there is a bunch of wiring. They were at some point in use but I found them connected to nothing.I have looked on my wiring schematic and found everything but this wiring. I did take some pictures but I can't figure out how do get them on here. They are probably not much help anyways. Anyone ever seen anything like this?

by pila Mon Dec 30, 2013 8:29 pm

What year is the car ? Maybe some wiring for the seat/starter interlock ?? My '74 Malibu had that wiring, and a relay on the fire wall for it also.
Only reason I found it was because when I was washing it one day in a car wash, it wouldn't start. Turned out that those wires had been chopped off under the dash, and one grounded itself, keeping the starter from working.

by dynchel Mon Dec 30, 2013 8:42 pm

[quote="pila"]What year is the car ? Maybe some wiring for the seat/starter interlock ?? My '74 Malibu had that wiring, and a relay on the fire wall for it also.
Only reason I found it was because when I was washing it one day in a car wash, it wouldn't start. Turned out that those wires had been chopped off under the dash, and one grounded itself, keeping the starter from working. (quote)
I went through similar problems when the relay (near the master cylinder) went bad. Everything else had Been removed/bypassed. I tried to get a replacement, No one knew what I was talking about. When I found someone who did they found me a nos one for something like $375.00. Needless to say I opened it up and permanently connected point a to point b. Haven't had a problem since.

by Mcarlo77 Mon Dec 30, 2013 9:59 pm

Wasn't that interlock system only connected to the driver seat?

Can't think of any other wiring in the passenger kick panel area other than for pwr window/lock and the speaker wires to the back.

by dynchel Mon Dec 30, 2013 10:16 pm

The interlock was for both front seat occupants. One reason (i read) was that people were putting grocerys (or other somewhat heavy objects) on the pass seat and the car wouldn't start. Cars were being towed to dealers with pi$$Ed off customers as to why there new car would not start.

by pila Tue Dec 31, 2013 12:30 am

Luckily, when mine wouldn't start while sitting in the car wash, a gentleman helped me push it out where I could check it out. Called the wife & had her bring a manual I have for a bunch of years, El Camino & Malibu, with electrical diagrams. Even then, it was a pain to find the problem.

by Mcarlo77 Tue Dec 31, 2013 12:59 am

dynchel wrote:The interlock was for both front seat occupants. One reason (i read) was that people were putting grocerys (or other somewhat heavy objects) on the pass seat and the car wouldn't start. Cars were being towed to dealers with pi$$Ed off customers as to why there new car would not start.

Now that you mention it, I do have a vague recollection of that.

by bitterfitter Tue Dec 31, 2013 8:32 am

I have gone through the seatbelt thing. I had the car not starting and I thought it might be that, so I went through it all and ended up bypassing the relay on the firewall. I will check my schematic for thw seatbelt wiring again though. Everything in the car works but there is this wiring that was there for a reason, and I do not know why? I could tuck it up away and never think about it again, but I still wonder why it is not on my schematics? If no one knows what it was for, I may have to start tracing it out just to satisfy my curiousity. The car is a 1974

by ant7377 Tue Dec 31, 2013 7:18 pm

Did the car originally have a stereo 8 track? Could be for the factory amp. That was over there and one of the factory power wires for the radio I believe is yellow.

by bitterfitter Tue Dec 31, 2013 7:53 pm

That is a good question? How would I figure this out? The car did originaly come with many options; including the CA1 skyroof option.....

The wires come from the drivers side and go up above everything under the dash, by themselves, and come out just before the glove box. Anyone with this type of stock equipment that can help me out here???

by Mcarlo77 Tue Dec 31, 2013 8:57 pm

I thought about the "amp" or "convector" as it's properly called, too...but, the three I have all have six wires leading to it from the radio...2 ea. blue, green, yellow. Plus, the wires would be running from the radio...not from the driver side of the dash near the headlight switch. You are confusing me in that originally you said the wires came out near the passenger side kick panel. Now, you state they are coming out before the glove box. Still, it's a mystery to me...

by bitterfitter Tue Dec 31, 2013 9:09 pm

When I found the wires they were stuffed down in the area behind the kick panel. When I say they are coming out before the glovebox, I mean this is where they reappear after traveling above the heating ducts and wiring under the dash.
I see the wiring for the convector on my shematic and these are not the same wires. I am starting to figure they may be for an option that came on the car. These options, like the 8 track, would not show up on my schematics.

by Mcarlo77 Tue Dec 31, 2013 9:18 pm

It's definitely not anything having to do with the 8-track radio. Don't know what other options came on these cars that would have wiring running that far over to the right side of the dash. Have you tried removing the passenger side door sill plate to see if there's any matching wiring running underneath it...like to the trunk?

by bitterfitter Tue Dec 31, 2013 9:25 pm

I have been redoing the car for awhile now. There are no door sills in place. The entire interior is removed, except for dash. The only wiring I have running to the rear is the rear harness that runs inside the car along the rocker panel. It has already been restored and placed back into the car.

I thought I had a good handle on the wiring in these cars. That is why this is bothering me so...

by Mcarlo77 Tue Dec 31, 2013 10:20 pm

Yeah...just don't know. I've gutted several of these myself and just can't think of what that could be for.

by bitterfitter Tue Dec 31, 2013 10:25 pm

I ran out to the garage to take a look at the wiring again. I am wondering if PILA was correct about it being part of the seatbelt interlock. I traced one of the wires back to a black plastic box mounted on the firewall just above my dimmer switch. I believe this black box is part of the seatbelt system. The yellow wires go into the major harness under the dash that is factory wrapped. I did notice, on the passenger side of the steering column a couple of, what look like warning buzzer boxes, on the end of some wiring. There is a gray one and a green one. The wiring going into the green one looks just like the wiring going into the harness (the yellow wires).

I double checked my schematic and it seems to be very sparce on the seatbelt wiring. It surely doesn't show all of it. Does anyone have a complete schematic of the seatbelt system? This might explain the original three wires going over to the passenger side of the car.

by Mcarlo77 Thu Jan 09, 2014 8:04 pm

You're probably way past this by now, but just wanted to confirm that this wiring you are wondering about is, in fact, for the seatbelt interlock system. I was out pulling some items off an early '75 Monte Carlo with power bench seat and this wiring was installed in the car. The passenger side wiring did run to some electronic box under the passenger side seat...ran back across the upper dash area to exactly where you see it connect to a five-wire connector. The wiring disappears into the main harness. Wires then emerge at the back of the main harness near the fuse box and run to that black switch box you mention located above the headlight dimmer floor switch. It was extremely cold outside and I didn't take the time to unwrap the main harness in that area to get an exact routing of the wires. If you're still interested in all this, let me know and I'll do that for you next time I'm out there.

I was photographing the junction of the pwr door/window wiring and captured what I believe is the black switch box in the background (behind the relay I have my finger on). I remember it having three or four wires to it...one pink, green, brown I think. You can see the three connected wires entering the photo on the upper right margin and continuing to near the main harness. It was disconnected at the five-wire connector...which can be seen haning below the main harness.

Wiring stumper for you guys 75mont10

by bitterfitter Thu Jan 09, 2014 10:24 pm

Eureka!! That is in fact the wiring that I was asking about. So that group of three wires runs under the dash and makes its way to under the passenger side seat? Everything you described is just what I was talking about. Say; what is that relay for you have your finger on? That is the one that is mounted above the parking brake lever to the kick panel? I assumed it was maybe for the A/C or heater...

by bitterfitter Thu Jan 09, 2014 10:25 pm

If I could figure out how to post pictures I would love to share some pics of the car; and the questions I come up with every now and then...

by RobW Thu Jan 09, 2014 10:40 pm

bitterfitter wrote: Say; what is that relay for you have your finger on? That is the one that is mounted above the parking brake lever to the kick panel? I assumed it was maybe for the A/C or heater...

The relay is part of the accessory power system circuit (power windows, power locks, power seat) that runs directly off battery power (ie. the circuit always has power). This relay keeps the power window system from getting power when the ignition is off.

Rob

by bitterfitter Thu Jan 09, 2014 10:51 pm

Thanks for the info. So this is part of my power locks and power windows circuit. I wish these things showed up on my schematic.

by thatfnthing Thu Jan 09, 2014 11:40 pm

bitterfitter wrote:Thanks for the info. So this is part of my power locks and power windows circuit. I wish these things showed up on my schematic.

The schematics for the power windows and locks (and seats, tailgates, defoggers, and other body-related circuits) appear in the Fisher Body manual. The Service manual does not have these. You need to have both manuals to have the complete set. There are a couple on ebay right now for $20.00.

by bitterfitter Fri Jan 10, 2014 7:36 am

I will get on there after work and get a set. Thanks again for all the help.

by Mcarlo77 Tue Sep 16, 2014 8:43 pm

So...after finally getting a chance to dig around under the dash on the Laguna, I realized it came with the Seat Belt Interlock setup, too. The passenger side harness is not connected to anything as the seats have been replaced. However, my curiosity with the wiring was rekindled when remembering this discussion last winter. Like Bitterfitter found, it's near impossible to trace the wiring up under the dash...so, I made a point to revisit that '75 Monte Carlo w/Interlock setup out in the salvage yard that had the dash removed and all the wiring exposed. So, got reacquainted with what went where, but then noticed this metal "START" relay (GM #1243384) plugged into the orange relay box on the engine-side firewall (above the brake booster). I then wandered over to a '75 El Camino and discovered it also had the Interlock...but, only had the white plastic protective cover over the exposed plug-ins on the orange relay box. My car didn't have either one on it. So, I'm curious...did cars come with the "START" relay originally? I would think not since the El Camino had a protective cover instead. Were they handed out by dealer repair shops when customers started bringing in their cars because they wouldn't start? Did GM finally wake up and include these with all new early production '75 models?

I know this is all really inconsequential as most everybody has disconnected or overridden the system...but, it's this kind of historical trivia with our cars that make for interesting discussions.

Wiring stumper for you guys 7475se10

by bitterfitter Tue Sep 16, 2014 8:52 pm

I may be wrong but I believe they all came with the "start" relay installed.
I have bypassed mine by opening the relay and bypassing inside. This way it is still there just not functioning. What a PITA system this was.

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