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Hey guys, Looking for some help / guidance. I have two issues I am trying to fix. I have pulled a wiring diagram with wire color codes, which has been helpful.
1) Door Ajar Light does not illuminate when the doors are open. I have replaced the bulb and the door switches . The Light Blue / Black wires at the switch look good and have no visible breaks that I can see as I have traced them in the rear of the car. At the gauge cluster where the light is located the wire is noted as Pink & Light Blue, this looks to be correct as per the wiring diagram. These wires from the socket into the wire harness does not have any breaks in it. The socket is different than the others in that there is no metal ring around the socket that would provide a ground. Is this correct? (see picture). Also when I put a test light to the center pin of the socket and ground it, the test light does not go on.
2) Wiper Door Override Warning Light. This is connected via a black wire directly into the harness. This seems to always have power and the light never shuts off. The wiper overide switch, below the steering column is not connected to anything (I need to address this issues also, not sure how and and where this switch connect to). Could this be the reason why the light is always on?
3) Seat Belt Lights. Thre is a Black jumper wire from the fuel gauge to the seat belt warning light. There looks to be a buzzer ( see picture). This looks correct per the wiring diagram. There is no bulb in the grey socket that would accept a #194 bulb. How does this work and what does the "push" button do?
Any insights on how to diagnose and fix these issues are
appreciated.
68 Cordovan Maroon Tri Power! Congratulations!! One of my favorites.
Originally Posted by Bigkahuna1966
Hey guys, Looking for some help / guidance. I have two issues I am trying to fix. I have pulled a wiring diagram with wire color codes, which has been helpful.
1) Door Ajar Light does not illuminate when the doors are open. I have replaced the bulb and the door switches . The Light Blue / Black wires at the switch look good and have no visible breaks that I can see as I have traced them in the rear of the car. At the gauge cluster where the light is located the wire is noted as Pink & Light Blue, this looks to be correct as per the wiring diagram. These wires from the socket into the wire harness does not have any breaks in it. The socket is different than the others in that there is no metal ring around the socket that would provide a ground. Is this correct? (see picture). Also when I put a test light to the center pin of the socket and ground it, the test light does not go on. Ok yes the pink/light blue bulb socket does not have the ground ring like the others, so that is correct. Me I would check fuses, loose fuses, wiring, wiring diagram and keeping digginguntil you get 12v+ at the socket
2) Wiper Door Override Warning Light. This is connected via a black wire directly into the harness. This seems to always have power and the light never shuts off. The wiper overide switch, below the steering column is not connected to anything (I need to address this issues also, not sure how and and where this switch connect to). Could this be the reason why the light is always on? I would check the wiring diagram, 68 is different from the rest there are some Wilcox and other info on the internet for 68 setup. MIght be the light only on is related to the disconnected wiper override switch.
3) Seat Belt Lights. Thre is a Black jumper wire from the fuel gauge to the seat belt warning light. There looks to be a buzzer ( see picture). This looks correct per the wiring diagram. There is no bulb in the grey socket that would accept a #194 bulb. How does this work and what does the "push" button do? Ok so this buzzer looking coil is actually an electro magnet that pulls the contacts in to illuminate the seat bellt light when the engine is started. When you push the black seat belt button, it disengages the circuit to this light and turns off the light. No sure how it resets or maybe this action is reverse from what I say. maybe the coil pulls or keeps the contacts open until no power and the contacts reconnect? Anyway that is the general principal. I would check for continuity on the coil and ck for a good bulb and if the push button is actually disengaging the contact arm when it is pushed. I would also take a couple of 6v lantern batteries in series (12v) and bench test it and see if you can get it operate.
HOPE this helps, Super nice 68 TriPower in Cordovan Maroon, Sweet!
Any insights on how to diagnose and fix these issues are
appreciated.
Thanks Darren
Last edited by 20mercury; Nov 16, 2025 at 02:08 PM.
In further research on #2, in late production ‘68’s GM changed the light from wiper override to headlight on light. My production date is August l, so late production. Might be related to an issue with the head light relay??
In further research on #2, in late production ‘68’s GM changed the light from wiper override to headlight on light. My production date is August l, so late production. Might be related to an issue with the head light relay??
Do not know. If me I would get a 68 and a 69 wiring diagram and see if I could understand how it is supposed to work. Sorry I do not know more.
'68 Center Gauges Wiring Issues
