What makes a blinker blink way too fast - bad ground? I hadn't driven my '78 in a couple of weeks, had to clean the contacts on the bulb for the dash left turn signal indicator before it would work, then I had to clean the contacts on the bulb holder(?) for the front driver's side blinker (turn signal, 1157 bulb - I think) before it would work. When I got everything working, it started blinking too fast. I thought that I would check and clean all of my grounds. Any suggestions?

 

Swap the 4 way flasher with the turn signal flasher and see if that slows them down. Might just be the flasher on its way out.

 

The non-electronic flashers in these trucks work by the current through the turn signal circuit heating up an element inside the flasher, hence the name thermal flasher. If it's blinking too fast, there's too much current going through the circuit, which is most often due to the wrong bulb being used somewhere (too low of resistance = more current = more heat in the flasher = faster blinking).

Try ranger's suggestion though; that will easily tell you if it's the flasher.

 

A burnt out signal bulb?