My uncle recently bought a 1982 GMC with the 6.2L. He started it up the other day and noticed that even after it warmed up the glow plug light was flashing.

I haven't had a chance to look at it and have never worked on a 6.2 or 6.5 for that matter.

Any suggestions on where to start or things to look for would be appreciated.

 

That happens from time to time. Mine will keep blinking for 5-10 min, depending on the weather. You can bypass the relay and run a manual switch. Shouldnt be anything to worry about.

 

Will "after glow" some but should not stay on long, Possible ECT sensor on way out or low coolant level not covering the ECT fully, or poor gnds for ECT sensor circuit, ECT to glow relay is what controls glow cycles.