Most electrical problems off all old cars are bad grounds! Even if they look good you should clean them up! And they are a lot in there’s GM cars of this era! I m professional mechanic and I (stil) own a lot of these type vehicles of the ‘80s,’90s and on! Start with the shop manual “ground” connections first! Just a tip! I always do that first! My Reatta had lot of problems with bad grounds and even totally corroded inside the electrical harness! Good luck with fixing it!!🍀
I never did trace all the ground wires. Sadly, I had to give up my Trofeo, but hopefully the new owner is successful in tracking down all the grounds. Thanks for the advice!
I went through a similar problem in my 89 oldsmobile eighty-eight , and it stumped me for months. I had tried replacing the headlight switch, with a used one, but it didn't work. Months later i bought a new switch and worked, turns out the used one was bad too.
Thanks for the idea.. I did change out the switch with another old one, so who knows if that one was broken also.. I'll have to keep my eyes open for a new light switch and try it!
I covered the light sensor and did some additional testing.. the sensor seemed to work to brighten the dash display, so I thought it was working.. but maybe that logic wasn't correct.
Most electrical problems off all old cars are bad grounds!
Even if they look good you should clean them up!
And they are a lot in there’s GM cars of this era!
I m professional mechanic and I (stil) own a lot of these type vehicles of the ‘80s,’90s and on!
Start with the shop manual “ground” connections first!
Just a tip!
I always do that first!
My Reatta had lot of problems with bad grounds and even totally corroded inside the electrical harness!
Good luck with fixing it!!🍀
I never did trace all the ground wires. Sadly, I had to give up my Trofeo, but hopefully the new owner is successful in tracking down all the grounds. Thanks for the advice!
I went through a similar problem in my 89 oldsmobile eighty-eight , and it stumped me for months. I had tried replacing the headlight switch, with a used one, but it didn't work. Months later i bought a new switch and worked, turns out the used one was bad too.
Thanks for the idea.. I did change out the switch with another old one, so who knows if that one was broken also.. I'll have to keep my eyes open for a new light switch and try it!
I tried to update this a while back. It's the light sensor in the dash that is bad. 😉
I covered the light sensor and did some additional testing.. the sensor seemed to work to brighten the dash display, so I thought it was working.. but maybe that logic wasn't correct.
Did you ever get the issue resolved?
Actually I have not! I am going to start working on this car again, and this is top on my list... so frustrating!