Engine/Transmission (1994 - 1998) Grid heaters not working, but "wait to start" is??

[JGheen]

Just another one of my issues after my cylinder head install are the grid heaters. I am not sure if they are working or not. I cannot hear them come on when I turn the key on but the "Wait to start" light comes on and goes out like they are operating. The volt meter on the dash goes low like the are powering the heaters and then when the light goes out the volts come up some like normal. Wouldn't the WTS light stay on for longer if the heaters weren't working since the intake temp is not rising? I am running a new intake air temp sensor and I used to be able to hear the grids come almost like a torch sound under the hood but not now. Any thoughts on where to start looking? Are the relays under the driver side battery prone to just go out? The truck hasen't run in over 3 1/2 weeks cuz of the headgasket issue, but would they just burn out after not being powered up for so long??



Thanks guys, Joe

 

[TMitch]

I had to change both of the relays on my '97. They are easy enough to check with a voltmeter and a helper to turn the key on. The WTS light will come on even if the heaters are not working.

I took the old ones into the local Western Star dealer and paid $11. 00/each for some new ones. Initially I had a disconnected push on connector for the relay activation circuit but still NFG when I hooked it back up so I tested the relays and both were bad.

I bumped the idle up a bit after the new relay install and the truck started like a dream in the cold weather.

 

[Got Smoke?]

best way is to unbolt the intake horn and turn the key then hold you hand OVER NOT ON! the heaters. Trust me if they are working you will know it! :-laf



If they aren't working do a search under my name and heater grids, you will find my fix thread.

 

[JGheen]

Thanks TMitch, I will give the relay test a try and hopefully its them, just curious as to why they would suddenly just go out and both of them for that matter.



Thanks Mark, but I will leave the intake horn on and try the relays. I am very sure there is nothing wrong with the grids themselves as I tightened everything up and checked all the insulators on the bolts which were good. I definatley don't want to go to the hospital with grid heater burns. :-laf I am leaning towards the relays just wondering why they would go out and if there is a bigger problem that could burn up new ones when i install them.



Joe

 

[tp0d]

Shouldnt be any noise when the heaters actuate. I had a noise before I changed my batteries. It was the high draw causing the batteries to boil i think. they were very sulfated. Got a set of 800cca from a local parts guy for 110 for the pair. .



You can check ohms to ground at the terminal for the heaters, should be a pretty low resistance, but both should be very close to each other. The ground is switched on the control relays. .



good luck



-j