beast

[beast]

the fuse in the under hood fuse box that controls the juice to the glow plug relay keeps blowing. 96 6.5 turbo in a 97 model 3/4 ton truck. any ideas where to look? thanks in advance and GOD bless!

[Hubert]

Any and all wiring under and around turbo. It gets dang hot under there and melts looming and exposes wires. Passenger side middle cylinders (2 and 4) the plug wires are kind of tight and under severe heat. The glow plug wires have fusable links that are suppose to protect circuit but may not be opening and the short blows the fuse???

Feel the wires and relay and see if anything is getting warm. If you can't find a short and/or its intermittent I would think relay is going bad but I don't know????

[beast]

i have checked all the above and the relay is new. i have even placed a circuit breaker in place of the 10 amp fuse to help me locate the problem. i may install a manual controller to overcome but would rather find the problem. just stubborn that way

[moondoggie]

Good Day!

When I was chasing a similar problem, I took one of the blown fuses & soldered a wire to each of the prongs. I then connected these wires to a load. In my case it was a 20A or 30A fuse that was blowing, so I used an old but functional blower motor; if I were chasing a 10A circuit, I'd probably use a headlight with both filaments powered.

Whatever's shorting this circuit will now not blow a fuse, but power your dummy load, with limited chance of damaging anything.

In the blower-dummy-load example above, I found out that some moron (ME) had wired the trailer lights so that when I put the truck in reverse, a wire was connected directly to ground. In a previous situation, we had an 83 Malibu that every couple weeks blew a fuse. I did this trick with a headlight for the dummy load, wiggled wires under the hood, & found the wire with the worn-through insulation. I can't imagine having found it any other way. The really terrific thing about this was that when I wiggled the wire, the dummy load headlight blinked on & off. When I was finished, I was absolutely certain I had effected a repair, which turned out to be the case.

If your short is always present, it's a little harder to troubleshoot, but at least you're not blowing fuses.

It might be wise to purchase a factory shop manual (I own one for every vehicle I've owned in the last 20 or so years), so you can determine everything that's on this circuit.

Good luck, keep us posted, & Blessings!

[sailun]

Any chance you over-tightened the stud on the new glow plug relay, and broke the stud and connection loose inside the relay ? It doesn't take much for this to happen.

Not sure if this would cause fuse to blow, or just glow plugs in-op.


Don't ask how I might know about something like this happening.

Ka-ching ! Back to the auto parts store !

[beast]

cool idea about the headlight, been wrenching all my life and dont recall that one. many thanks and will give it a try!salun that wasnt the problem but thanks also!

[JohnC]

Dunno for sure about the '96, but for the '95, all that fuse covers is the glow plug indicator light and the sense wire to the PCM. Power comes from the switched side of the glow plug relay, through the fuse and to the lamp and PCM.

[BiggR]

the fuse in the under hood fuse box that controls the juice to the glow plug relay keeps blowing. 96 6.5 turbo in a 97 model 3/4 ton truck. any ideas where to look? thanks in advance and GOD bless!


I had this same exact problem on my '95, turned out to be a short in the fuel heater, I just followed the GM service manual for diagnosis, and it said the fuel heater was bad! I unplugged the heater and ran that way for a while(summer) then bought a new one, I've not had a problem since!! FYI it is only a few dollars more to buy the whole filter assy thru GM than to just buy the fuel heater, and you dont have to tear down your old one!!!! Hope this helps!!

Bigg R

[beast]

i will check that out as soon as i finish installing the new water pump. sounds like that could be it! thanks Bigg R and everyone else that replied!

[beast]

I looked at the wireing schematic in Chiltons last night and that is exactally it! should have looked at that first. thanks for the nudge Bigg R. Also has the vacuume circuit and that answerd all my questions on that! DUH! on my part.I didnt realize how well writen i is untill last night. Many thanks and GOD bless!

[BiggR]

Glad to help! And Merry Christmas to you!!!!

Bigg R

[beast]

I got the new waterpump finished last night and also opened up the top of the intake by cutting out every thing but the egr tower and tightend the boost spring about 4 turns. really ran alot stronger! also found i could move the wire going into the fuel heater and the relay would click on and off. orderd a new filter heater assembly and that will fix that. once agin thanks to everyone that helped, i really am enjoying these forums, there is a wealth of information here! Merry Christmas everyone and GOD Bless!!!

[beast]

when i unpluged the fuel heater i still had a problem. after looking closer i found two other wires to the filter for the water in fuel indicator. one wire was pulled loose and apperantly shorting. i pluged the heater back in with the water indicator wires taped off and all is well now. i stll plan to replace the unit so every thing will work as it should.