dash lights not dimming

[8631z]

i have an 86 turbo that the dash lights do not dim. the lights go on with the headlight switch but do not respond to the dim buttons. i have taken out the Timing control unit. (not fun to get to) and tested the feed from the light switch and the dimmer switch. they all tested good. im under the impression that the tcu is bad. i just want to make sure i covered all the bases. i also had to replace the digi dash and the voice control as that was failing too.

on a side not the red lights in the door do not work. i have narrowed the cause down to i believe diodes in the dash somewhere over the glove box. can these be reached with out pilling the entire dash?

[evildky]

no aftermarket stereo or alarm? I've seen people hook things to the illumination circuit and screw things up.

[8631z]

it has an aftermarket stereo. i just bought this not that long ago. and its had some interesting things in it. ill try disconnecting the radio and seeing. im not sure if the radio itself has an illumination circuit. but the radio itself is also broken too.

[evildky]

quite often people hook an aftermarket stereo ground wire to the factory stereo illumination circuit. The OE stereo uses a chassis ground and no actual ground wire.

[8631z]

Quite often must be referring to this black wire hooked into the illumination circuit. I'm now remembering that it does not have a ground wire. I wish I checked before looking for the tcu but at least I know where it is and that the manual lied about how easy it is to get to.

Dash is dimming again!

[evildky]

Glad we could help.