70 Yenko Electrical Help--PLEASE!!

[TDW]

Do all of the other bulbs light up in the dash? If so, you can pretty much eliminate a grounding issue with the board.

[rcc]

That is 100% correct.

[TDW]

I would test both indicator bulbs, then go from there. Can you access the bulbs? I don't remember if they can be taken out without removing half the dash.

[resto4u]

It has to be the bulbs or the dash printed circuit. sometimes the copper melts and the circuit is open with no current making it to the bulb circuit. The dash plug may not be making contact to the printed circuit. I had no dash lights, i unplugged the connector and pulled printed circuit up flat and lightly used a hair dryer just to flatten the bend from being plugged in all those years. I plugged it back in and have had dash lights ever since, going on two years. Roger

[rcc]

Hey Tony and Roger;

Thanks for the direction. While I'm up under the dash checking the integrity and grounding of the light bulbs, please remind me of the location of the printed circuit board.

Thanks,

Rick

[Tidmack]

The printed circuit board will be a sheet laying against your instrument panel that your bulbs make contact with when you plug them in. Be gentle while removing bulbs, as this circuit board is pretty fragile and can tear easily.

Jeff

[earntaz]

Rick -- printed circuit extends from the left to the right side of instrument cluster ... attached is a pic of the dash circuit.

[rcc]

Thanks for the schematic!

Happy 4th!

Rick [img]<<GRAEMLIN_URL>>/flag.gif[/img]

[earntaz]

Rick -- I was scanning the wiring diagram and found something interesting. The wires that connect to the dash lights (hazard and turn signal) are paired with front and rear hazard/turn light wiring at the connector going to the column switch. It appears the column switch is working as advertised because you have working turn signal and hazard. As indicated by other members here, the problem seems to be at the instrument cluster connector or with the printed circuit.

Check the wiring diagram I sent you ... TAZ

[rcc]

Hey Taz;

Man, I am about to go crazy with the electrical issues. I had to order the correct turn signal/hazard wiring harness. Should be here the end of this week. I did pull the old one out from the steering column (4 hours R&amp;R). It looked OK so I cleaned it up and put it back in. I did determine that the horn is bad but the relay is good. I found a broken horn part in the steering column and &quot;jury-rigged&quot; it. Still haven't been able to determine if I have a circuit board issue--I will in the next day or so.

OK, here's what happened after I put everything back together. Lights, horn relay, turn signals Haz signal all work correctly . However, once I have reconnected the battery and tried out the lights, etc. the rear end brake lights stay on UNTIL I either R&amp;R the neg battery cable or R&amp;R the brake light/Haz fuse. What in the world is causing this to happen?

Many thanks for all the help and suggestions.

Rick