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Where's the ground and other mysteries... Posted by Gary Stottler [Email]  (#1463) [Profile/Gallery]
(more from Gary Stottler) on Mon, 23 Aug 2010 11:56:09
In Reply to: Dash lights dim with headlights on, LJB, Fri, 20 Aug 2010 12:38:47 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I think there are two things to look for here:
1) Grounds - yes, I think there is a ground point under the dash and the dash lights likely would go to that. Unfortunately, I don't know where it is, so you may have to pull off the trim panel under the steering wheel and stand on your head to look for a bunch of black wires bolted to a stud somewhere. You can look on the wiring diagram to get an idea how many wires are on it.
2) Power supply - the other thing that could cause problems is on the power side - the voltage falls (due to high resistance at a connector or fuse) when the headlights come on and start to draw current. Test with a volt meter at one of the dash light bulb sockets with the parking lights vs. the headlights and see if the voltage drops when you turn the headlights on. Try grounding the meter both to the ground side of the socket and to a known good ground, that might help tell if it is a ground problem.
As an auxilliary to that last bit, you might pull the dimmer out of the dash if there's enough wire and check to voltage output to the dash lights at that point as well as the 12V input to the dimmer. I assume that comes from the same source as the lights.
The other thing to check is, I **think** that the headlights and the parking lights are powered by separate fuses, and the parking lights are "battery" power (hot all the time) and the headlights are "ignition" (hot only with key on), so you might be chasing the source of the voltage drop with headlights on pretty deep into the harness and looking at connections between the battery and ignition switch, back to the fuse block, etc.
Good Luck!
Gary
posted by 198.208.25...
_______________________________________ Gary Stottler
, Mon, 23 Aug 2010 11:56:09 <-- Viewing This Message
, Fri, 20 Aug 2010 17:09:34
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