I'm thinking this question has been raised before, but I thought I'd ask anyway. I live in a very warm climate, Temp is above 40 when I leave for work most of the time. When driving most of the time, it seems kind of useless to have the glow plugs operating after I have already run the truck. I know not waiting until the indicator goes off is not good for the system, but are the glow plugs really needed after I have been on the road for 200 miles and just stop for fuel? And, does anyone make a temperature controlled unit that does it automatically? I can put in a rocker or toggle switch, just want to know if I'd damage something if I did.

 

The glows are controlled by the ECM and coolant sensor in the water crossover on 94+.

On 93 and older there is a thermal switch on the rear of passenger side cylinder head that controls the glow duration.

If you are getting long glow cycles on a hot engine you need to look into those sensors/wiring.

 

Usually on my 93 when its hot outside and the engine is warm the glow plug light dosent even come on..im not sure about newer years though

 

93 is much less sensitive than the computer controlled versions.