Question If the glow plug relay is bad, in that it engages relay, to burn up glow plugs.....will this screw up the glow plug module to the point that it is damaged and has to be replaced AGAIN ?!? I feel like I am chasing my tail.....
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Have replaced the glow plug relay,glow plugs and glow plug module card and the 2 small wire on the glow plug relay are always hot (engageing the glow plug relay full time). I am nearing my wits end....any ideas ? If I switched the 2small wires on the glow plug relay, would it make any difference in operation ?
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Is their a special reason a Borg Warner S 55 glow plug relay is recommended over a GM 6.2 Diesel relay ?
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After changing the glow plug relay and engaging the ignition key glow plugs will just about destroy themselves from overheating. Am I correct in thinking that I need a new glow plug module circut card and that this plus new glow plugs will solve my problem ? Also do the firewall resistors ever fail and that this also might be a part of the problem ?
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For the M-1009 Blazer..What is the voltage/amps coming across the glow plug relay when relay is engaged by turning on ignition key(12 V)? I have been told that the 24 V batts. supply 24V/ hi amps. to the firewall resistors which brings it down to 24 V/low amps, which then crosses the top part of the relay then down to the glo plugs...What does the glow plug module do in all this ? Are the military glow plug modules the same as the civilian glow plug modules for I am pretty sure this is what I need ? . Relay has been replaced along with glow plugs. Fuel system is good. -09 still will not start. Thanx
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It is correct that 24 volts go to the resistor.
The hi amps/lo amps....?
The glow plugs are twelve volt. I would say the resistor drops the voltage to 12 to 13 volts when the glowplugs are connected.
Amps are more a matter of what a load draws, not what a battery puts out, although I will say the battery makes available more amps than the glow plugs need.
The relay is a 12 volt relay, and should carry the load of the glowplugs, whatever it is. I'd guess probably about 20 amps, but I haven't measured that in years.
I will say, if you have a little plastic oblong relay on the firewall, I would replace it. They overheat, and melt a plastic internal part, and even if you hear it click, may not make good contact, or worse yet, they make contact all the time, and burn up the glowplugs.
Replace it with a Borg Warner S55 relay. Looks like a Ford starter solenoid, but it isn't. The small studs are NOT internally grounded.
If the relay sticks closed for any reason, all eight glowplugs will be destroyed in just a few minutes.
It is the job of the glowplug module to properly time the application of the glowplugs, according to temperature of the coolant.
I have never seen a civilian module like the military version. I have known of people who control the relay with a push button, and have successfully operated their system for years.
Orriginal military parts can be located at
http://www.memphisequipment.com/
but I would never install that plastic relay.
You might even get parts and service manuals from them, but I'm not sure.
Van
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The glow plugs will destroy themselves if the relay stays closed too long, for whatever reason it stays closed.
It can stay closed because the controller is bad.
It can stay closed because it is connected wrong.
It can stay closed because the contacts inside stick.
The firewall resistor....I would think if it fails, it should fail OPEN, but I have had good luck disconnecting from the resistor, and connecting the relay to 12 volts, which is available on the firewall, at that black plastic diamond shaped power tap. It carries the glow plugs just fine.
There is a long, intricate proceedure for testing the controller, and I don't have a copy of it.
But I have heard from some people that do away with it, and use a push button to manually control the relay. I would want to check how long a good working truck keeps the relay closed, and try to mimmick that time.
Van
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The relay just needs to have isolated pullin windings, meaning the small terminals are not grounded. Power goes to one of them, and the controller completes the ground by grounding the other.
If you have a 6.2 diesel relay that will work like that, then use it.
But if the relay closes when power is applied to a small terminal with just the base of the relay grounded, then the military controller won't work.
Van
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One of the small wires should be hot when the ignition switch is in run.\r
The other small wire goes to the controller.
Remove at least one of them from the small stud, and then see if they are both hot all the time.
With the isolated winding in the relay, if they are connected to the studs, both will show just about the same thing.
AnswerHello Ed,
Yes,If the glow plug relay is bad, incorrectly wired, or the wrong one, it could screw up the glow plug module to the point that it is damaged and has to be replaced again.
I have seen a system test proceedure for the connector that the module plugs into, but don't have a copy of it.
It tells what voltage or ohm reading each contact should have, at different times, like key on, key in start, key off, etc.
But also, the correct glowplugs must be used.
Van
