Glow Plugs Inop

[johnanc]

Finished install of new long block in '94 K2500. Glow plug dash light doesn't illuminate. No power to 5 amp fuse (fuse intact). New glow plugs, new coolent sensor, new fuel filter assembly installed. Starter engages, fuel to injectors. All connections to glow plug relay and glow plugs seem intact. Appreciate any help.

[john8662]

You're talking about the fuse in the underhood fuse panel right?

Take a test light with the ignition key on run and see if you have power in the pins in the fuse panel.

Perhaps the fuse is in the wrong place? There are several blanks beside it.

J

[johnanc]

Didn't realize there was an underhood fuse panel, I'm not off to a good start I suppose. Where is the underhood fuse panel you mentioned? I've found the glow plug relay (rear left cylinder area by the firewall). I was looking at the fuse in the common fuse area inside the cab, it's true there are several open spaces surrounding the glow plug fuse.
I have GM's Electronic manual, not that I'm great at figuring out schematics, and it looks like some of the components I replaced (water temp sensor, fuel filter, etc) are part of the Glow Plug circuit.

[gmctd]

Glow plug supply is fusible-linked to the power bock on the passenger-side upper firewall.

[oilburnertoo]

'94 doesn't have an underhood fuse panel, that started with the '95 model. On the right side firewall [pass side] there is a junction block behind a plastic cover that has some fuseable links, a few relays, and maybe a couple of inline fuse holders.IIRC

[redbird2]

I had a 94 3500 in service truck it had the fuse block under the hood also. for some reason I remimber reading somewhere about the 94,95 getting the glow plug relay to cycle the first time was pain. I seem to remimber the one contoller I replaced on that truck did want to work after I installed it so I jumped across 2 main power lugs to get glow plugs to come on about 25 sec was all. so I could move truck into the shop as it was setting outside in the winter. I pulled in shop shut off, got out voltmeter was ready to start test turned on key glow plugs came on never gave me problem again until replaced the engine had to do the same thing.
I had forgot all about this until I was typing this just now

it would hurt to try this
good luck

[johnanc]

Redbird, When you mentioned the "two main power lugs" were youtalking about the glow plug relay?

[redbird2]

yes the 2 lugs stick out of the top of the controller one is battery hot the other goes to the glow plugs