I've been chasing ground and electrical issues on my 1967 Firebird that are causing inconsistent instrument warning light problems. Thanks to all the expert advice here, I have most of them fixed now. I am down to one remaining issue. My brake warning light slightly glows on when the car is running and when the ignition is in the Acc position. I have tested the park brake switch and the brake distribution block switch with my multimeter and by grounding each wire to make sure the lights come on. Both switches test correctly when in the on and off position.
The only way I can get the light to go off is to unplug the brake pressure switch. At that point, the park brake still works as it should. But,I would not have a warning light come on if there is an actual problem with brake pressure in the future. Before I throw another $100.00 at a new switch, I wanted to see if anyone else has had this issue or if there is another test I can do. To clarify, I removed the distribution block and tested Ohms between the block housing and the switch connection. This test showed a completely open circuit (1 on my Ohmeter). When I take a small pick or drill bit and stick it in the front or back brake line hole and push it, the OHMS go to zero which grounds the circuit and the light comes. Even though this switch seems to test okay, I think it must be the issue since unplugging this switch is the only way I can get the slight glow to go off.
Thank you. Think i'll go ahead and put in a new switch. Chasing electrical gremlins in these cars is time-consuming. But, at least the parts are available and relatively inexpensive. I am ready to move on to something less time consuming (but more expensive, Im sure.
The car had been sitting since 1978 when I bought it in 2020. I have already replaced the circuit board since the original was pretty crunchy. I tested everything and replaced several rusted/broken light sockets, secured electrical connections, put in a separate ground wire, etc. Everything seems to work now as it should except the dull glow. I ordered the new Brake Distribution Switch this morning and will update after I get it installed. I've got to think that the switch has some sort of short to ground somewhere in it since the light comes on very bright when I ground the wire and the only way to get the light to go completely out is to unplug that wire from the switch. Thanks again for your suggestion.
Thanks to all for your suggestions. I installed the new Brake Distribution Block this morning. Problem solved. Since the old switch tested okay, when I have some time, I am going to remove the switch from the old block to see if I can figure out where it is shorting out to ground since that can be the only explanation at this point. Thanks again. Great info from the experts here is much appreciated.
