I have a 1984 GMC Pickup 6.2 Diesel motor. I'm not getting an fire from one side of the glowplug relay ?

I have a 1984 GMC Pickup 6.2 Diesel motor. I’m not getting an fire from one side of the glowplug relay that actually goes to the glow plugs. A few of the glowplugs are bad, and I’m about to change them. Will this cause the relay not to put out current to the glow plugs?.

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5 Responses to I have a 1984 GMC Pickup 6.2 Diesel motor. I'm not getting an fire from one side of the glowplug relay ?

  1. bestwrencher October 21, 2010 at 5:35 pm #

    the relay is just like a starter relay, but I think it is module controlled, I know newer ones are but i’m more experienced with the 6.5 . So cold when the ignition is first turned on the relay should click loudly power should then be sent to plugs but if no loud click then take test light and check large power to relay and small wire that activates relay, I know on a newer one bad glow plugs cause a code and the module wont activate relay, so you may want to replace glow plugs, then clear module by disconnecting battery for a minute. any questions is ok

  2. Dr. Gonzo October 21, 2010 at 5:35 pm #

    yeah man. If you are replacing any then I would replace them all.

  3. G-man 1 October 21, 2010 at 5:35 pm #

    No the relay will feed the glow plugs, I would replace the relay first then retest the glow plugs. You stated a few glow plugs are bad but not say how you tested them. The relay is much cheaper to replace , start with that, change the plugs if you are sure they are bad. Good Luck.

  4. Jad D October 21, 2010 at 5:35 pm #

    based on description and current situation with your truck i would have to highly suggest that you consider selling that piece of shit. good luck.

  5. dirocyn October 21, 2010 at 5:35 pm #

    I’m not sure what you mean by "not getting any fire." If you mean the glowplugs are not getting hot, then yes. A glowplug can fail so completely that there is no circuit between the relay and ground, new glowplugs could fix that problem.

    If by "no fire" you mean there is no voltage (tested with a voltmeter) coming out of the relay, you have (at least) one of four problems: Power is not getting to the relay, relay is not getting a signal to turn on, relay is not grounded, or relay is faulty.

    A relay works a lot like a starter solenoid. A small + voltage powers up an electromagnet, which moves a plunger, which closes the circuit in a larger amperage wire to your glow plugs. That electromagnet won’t engage unless it gets the + voltage and is grounded. If you turn the key with the hood and driver door open, you should be able to hear the relay click.