I have had trouble with the turn signals on my GMC 4905 since virtually the day I bought it.
I have replaced ground wires, bulb bases, bulbs, wires, etc. but this week I went to check the turn signals and I had nothing!!!
I though ---Great!! The Flasher unit finally gave up the Ghost!
So I started tracing the power. First I started at the flasher unit. I popped the connector apart at the flasher unit and checked the fuse--Well it is good. Next I checked the voltage which was reading 9 volts--WHAT???
Next I moved to the connections at the Driver's seat junction panel. Good at the circuit breaker at the driver's seat junction box(after removing the 8 screws that hold the panel cover). I sure wish I had put the driver's seat on some sort of quick disconnect instead of re-using the factory base. It is hard for old fat people to lay prostrate on the floor to get to those bottom bus bars.
So then I moved back to the flasher unit. I checked the contacts inside the inline fuse. YES--Totally corroded--after attempting to sand the contacts still only getting 11 Volts. So, I cut off the end and check the voltage to ground--24 Volts. OK, so after a trip to AutoZone for a new inline fuse holder, and a quick install I now have flashers!! This bad connection has probably been the source of my problem all along!
BUT, since I installed LEDs on the rear they blink REEEEAAAALLLLY SLOOOOOW!!
I know somebody here solved that with a resistor in parallel with the positive line to the LED, but what I forgot was the resistance needed and what the nomenclature is for that resistor. Since Radio Shack is long gone I need some suggestions for where to get these resistors.
Any and all help is greatly appreciated.
Steve Toomey