I have an 86 Iroc that has two issues. First the parking lights wont turn off with the light switch. When the car is off the lights go off. But when the car is running the parking lights stay on. It doesn't affect the blinking of the turn signals or brake lights. Everything seems to work normally except for that. I feel there is something back flowing into the parking lights. Could this be a bad relay? What would make them stay on? Ive double checked the grounds under the hood and everything looks good. Ive been fighting this for awhile.

Second problem (might be related) I swapped from the old belt system to a serpintine system from a 90's truck. This caused the alternator to switch sides. I used a pigtail to adapt the newer style alternator and ran new battery cable. It doesn't seem to be charging the battery. Reads around 10-11 volts while running. Both the battery and alternator check out fine. Any idea what could cause this? Bad pigtail?

 

Sounds like somebody rewired your lights. It's too dark out for me to see exactly what they hooked to what, you'll have to trace the wiring and find out for yourself.

See https://www.thirdgen.org/forums/elec...onversion.html for alt info.

 

Tell me , does your car still have the factory radio , or is there an aftermarket radio in there ?

If it is an aftermarket radio , it's a common wiring mistake made by some folks to end up with the dash lights (and by default the parking lights) connected to the key on +12 Volt source , which causes the exact problem you describe .

 

Yes it does have an aftermarket stereo. I'll take it apart tonight and look at those wires. The stereo would've been the last thing I checked. Thanks for the help.

 

Ok , so now that we know you do have an aftermarket stereo system , here's exactly what to look for ;

The wiring harness coming from the dashboard into the radio will of course have many wires . The three wires we're interested in are the brown wire , the yellow wire , and possibly the grey wire . The brown wire is fed from the dashboard lights and is there to turn on the radio's backlight illumination when you turn the headlights/parking lights on . The yellow wire is keyed +12V . If the yellow and brown are connected together by a mistaken installation , every time the key is on (or in the acc position) the brown wire will "backfeed" the +12V into the parking light circuit .

I am enclosing a wiring diagram of the factory radio installation . the diagram is dated 1992 but the wiring colors will be the same . PLEASE NOTE that there are some wire colors that are reused more than once , such as the left rear speaker having a brown wire even though that color was already used in the illumination circuit . In other words , you've gotta make sure it's the correct brown wire your investigating , lest your troubleshooting fail due to not investigating the correct brown wire . Same for the color yellow , there is of course our keyed +12V on a yellow wire , but so too does that left rear speaker incorporate a yellow wire ! Also of note is the grey wire , this is from the dimming circuit and it too must be checked to make sure it's not mistakenly connected to the yellow (keyed power) wire .

I can't think of any other helpful suggestions here , but if you have any further questions feel free to ask .....

 

I took the stereo out last night. It's on an aftermarket harness so nothing has been cut. I took the harness off thinking it might be the harness. I testing the wires just like your diagram and they all match up. But Im still having the parking light problem. Could there be a relay out? Possibly the light switch is bad? I found 3 grounds under the hood and cleaned the paint and rust to get a good contact. Still nothing.

 

Ok , so it's likely not the radio . On to the second question , does this car have any kind of aftermarket alarm system and or remote start system ?

I ask this because most alarms and remote start system do have circuits that connect to the car's lighting system , to give the "confirmation flashes" when setting the alarm or starting the car remotely . When you look at the wiring diagram for your parking lights it's a pretty simple circuit that starts out at the "tail" fuse , goes through the headlight switch , and then on to the bulbs themselves through the brown wiring with no relay involvement whatsoever (The only relays in your lighting system are the 3 for the headlight doors and if you have the factory foglights there will be a relay for them too , but NO relays in the parking light circuit as per your wiring diagram)

I will enclose the circuit diagram for your taillight circuit , as you can see there really isn't a way for the switch to fail that could supply key on power to the circuit , and there are no relays , so the only logical conclusion is that somebody somewhere has tapped into that taillight circuit somewhere with key on 12V power , it's just a matter of finding out where ....

 

I appriciate your help. It's fairly virgin as far as wiring. I have't found any cut or spliced wires anywhere. I'll print the diagram and start tracing wires. Sounds like a fun weekend...

 

I traced your diagram through all of the parking lights back to the rust colored fusable link. Would this mean the link is bad or do I have it connected to the wrong spot on the starter?

 

On drivers side frame next to steering box.
Spent most of the evening tracing wires. What I found was this connection causing the parking light problem. I unplugged it and everything works fine. Any ideas why? This plugs together perfect and seems like it’s supposed to go together but it’s hot with the key on which puts power to the parking lights.

 

Check the RPO codes, the car may have a daytime running lights option. Here are a few codes for DRLs: T65, T61, and 9H8

RBob.

 

Wow , nice find ! And Thank You Rob , I had no idea our cars were factory equipped with DRLs . Did the DRLs operate the rear as well as the front lights ? And if not , if they only operated the front lights like the DRLs of today , I wonder why chixon's tail lights were on with that plug plugged in ?

 

I don't know enough about DRLs on 3rd gens to answer your questions. It may also be an export only option or such.

chixon: regarding the swap to the serpentine setup, be sure to swap the water pump out for one that was used on a serpentine system. It is known as a reverse rotation pump as it gets spun in reverse from a v-belt pump.

RBob.

 

For a time, GM offered over the counter kits to add DRL to any GM vehicle.

My friend and I had had matching Buick Century wagons at one time. My wagon had DRLs from the factory, his didn't. So he added them. Don't ask me why.