gettin to be that time a year again and im just wonderin if there is any easy way to check the glow plug relay on my 97. we've had a few cold mornings round 40 or below and the truck havin a little rough time startin up. any help?

 

super easy. get a test light on it. the one big post is always hot. the other big post is the switched power. clip the wire to the switched post and then sit in the truck and ground the probe end of the test light somewhere inside the cab, almost anything bare metal will work. turn the key on and if it lights up you're good to go. i wired up a led to mine so i have a more permanent test light.

 

Also check how long it is on for... On a stone cold start, it could stay on upwards of 120 seconds...

 

wouldn't the length of time it's on for be affected by the PCM? not the relay?

 

search western plow gpr I ordered on last year quarter of price of stancor works well