Topic: Electrical issues

[h3bubba]

I have a 79 T/A with a 403.  I am having issues with the instrument cluster lights not coming on when I turn the head light swith on.  I keep blowing the 4amp fuse.  I have an electrical diagram, and have been chasing wires all day to no evaile.  the cigarette light works as do the interior courtesy lights when I open the door.  all the bulbs are good and from what i can tell i have it all grounded correctly too.  I am geting 12 volts across the fuse.  any help would be very nice.  thanks.  

Pete

[ta78w72]

Unplug the white connector at the back of the cluster.  Turn the ignition on and the lights on.  Check pin 1 (the grey wire for 12 volt).  If you don't blow the fuse with the cluster unplugged, then you know it's a short on the back of the cluster.

If you blow the fuse with the cluster unplugged, then you have eliminated the cluster.  Check the other gray wires...like the cigarette illumination, the console light, and the fuel volt lights.  You'll have to follow the leads and check for shorts....not fun.

Also, it would be real handy to have a spare switch laying around.  I have them and would check that in my car first thing.  I always like to check moving parts first....cluster second because that circuit on the back of the cluster tends to flex and break apart.  If the fuse blows with the cluster unplugged....try another switch cause tracing wires is boring and something you want to do last.