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95 3500hd no glow Cycle

chevyCowboy

chevyCowboy

I might be crazy but i ain't dumb
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Location
Springfield Nebraska
Im working on a 95 for a friend that the gp dont cycle as they should. I checked all the gp and replaced 2 that where question able. Replaced coolant temp sensor in crossover, and replaced gp relay, and they still dont work. All grounds seem tight going to try and clean a couple up better. Im puzzled by the fact that with key on i do not get any power at the 10a fuse in under hood fuse block for gp.

Does any one have any other ideas?

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Check ECM for codes. Do you have a scanner to command the GP's on?
 
I do but This is obd1. I did flash the codes and had a code for gp circuit relay fault and that is why i changed it

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Have you measured to see if there is voltage on the GP controller?
How about load testing the batteries one at a time?
Do double check the fuse again? I had experience that sometimes good fuse are not good.

If that still not solving it, you really need ACDelco part for this.
Anything that say relay/controller, switch, sensor are very particular and the aftermarket brand are not up to par.
You can try exchanging it to see if you get better parts from Napa.
You are the quality control.
 
I thought there was an option to command the glow plugs on with my past 1995, but, it's been awhile.
 
The batteries are not very good i will try a different set out of my truck. I didn't use a meter but test light shows voltage at controler

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Two good batteries seems to have been the missing part to my puzzle. Seems strange that it would crank over but the glows wouldn't work

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The glow plugs fuse does nothing for the glow plugs. That glow plugs fuse only fuses the wire that runs from the glow plug controller to the glow pmug light in the cluster. I know it sounds stupid, but thats because it is that stupid. Found this out when I wired the wire that was at that fuse to the wait to start wire coming out of my duramax ecm.
 
The Glow Plug Controller is just a dumb relay on 1995. Look at the wiring diagram then get out the multi meter. Pink wire the one furthermost to the passenger side on the relay connector plug should have 12v with ignition on. Did the fuel heater short and burn up the glow plug fuse or fusible link? Maybe 2 fuses labeled Glow Plug? Center yellow wire gets 12v or 5v from the ECM to turn the dumb relay box on and then the signal goes away to shut off glow plug relay. Center black terminal/wire is ground. So check ground, ground with ignition on and then the 12v. Last put meter on windshield and leave ignition switch off for 30+ seconds. Hook it up to the yellow wire via backprobe and watch it while you turn the ignition on. It should get a signal from the ECM 5V or 12v.

Want to retry it? Wait 30 plus seconds for the caps in the ECM to discharge and the ECM to completely "Die" or you will even get inconsistent STS and SES lights for the bulb check: Let alone glow plug activation.

Note no volts to ECM glow plug signal for whatever reason trips code. Bad relay, no voltage to relay glow plug contact, no power to relay, bad ground to relay, missing relay.

http://www.dieselbombers.com/attach...893744-95-k2500-glow-plug-relay-wiring-12.jpg
 
Was just going to say the FFM heater can burn up and then GP relay won't work. WW beat me to it.
 
On my 95, I swapped a GP controller and WG solenoid before finding out the ENG-I fuse was bad and causing all the issues.

ENG-I fuse was bad because the fuel heater died.

Luckily parts were off a parts engine, so just labor. pulled them off, put old back on, unplugged fuel heater, put new fuse in, live boost and GPs again. :)
 
No i was helping a guy out that helped me out. It is for sale though its a 95 c3509hd with nv4500 and pto hoist dump box 80k original miles

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