What is it and why did it smoke.

tbearatkin · Aug 31, 2010

Glow plugs were all no good I changed them all from stock to AC60A and it started right up. However I noticed that the charging gauge was in the low yellow zone on the gauge checked the batteries and low volts 11.8 from the alternators (both brand new) then I saw on the firewall behind the air cleaner smoke coming from behind a metal plate.

Killed the engine and took the plate off and behind it was this. Looked in the cd manual (can'' wait until I print them) but could not find a picture of this thing.

After lunch I went back out and it started right up gauge was at the bottom level of yellow and green and both batteries were charging at 13.3 and 13.6 volts.

Question is what the heck is that thing in the picture. Looks like a huge resistor of some kind and what would cause it smoke when running one time but not the next.

Thanks a bunch I dont want a hulking melted piece of artwork in my yard.

edit to add. Just got it on Saturday, previous owner drove it about 2 hours to get it here and it was running fine then except it needed glow plugs. He replaced both alts/batteries and starter relay prior to selling it and he has been fixing them for awhile so I think he knew what he was doing when he changed everything.

grayw0lf · Aug 31, 2010

If I'm not mistaken, that is the glowplug resistor pack.

jwaller · Aug 31, 2010

13.3 and 13.6 is still low. should be about a volt higher on both.

tbearatkin · Aug 31, 2010

Okay somobody at a Army rebuild place said the book called it a
a battery booster resister goes to the glow plug relay but still no idea on why it was smoking. The volts to the batteries was at idle alts are one 100Amp the other is a 60amp I think. Found it in the manual still looking to see what it does
TM 9-2320-289-20P
FIGURE 39. BATTERY BOOSTER RESISTOR

Wonder if I should have changed the GP relay when I went with the AC60 GP

notsosanestan · Aug 31, 2010

I believe you can delete that by taking the wire of the 24v buss bar behind the batteries and connecting it to the front battery or the negative on the back one

Chief_919 · Aug 31, 2010

That resistor heats up when the circuit is energized. If I am not mistaken when the glow plugs are bad in a CUCV no electricty will flow. If they were bad for a while that means the resistors didn't get warm for a while, and the first time they did you burned off the dirt anbd grime that had settled on them.

beanman1 · Aug 31, 2010

ok ok here to the rescue that thing in the pic is the glow plug resistor. 24v power goes in and when the key gets turned on and the glow plug relay get energized it drops the voltage from 24v to 12v and lower but when a glow plug is bad it raise power to the rest of the glow plugs causing a chain reaction burning out glow plugs. If the resistor was smoking it went awol on you so what you need to do is bypass it or get a new one. To bypass it you need to disconect it from the battery junction block on the fire wall and from the glow plug relay. Then get some 10 gauge wire or bigger and run it from the negative terminal of the second battery (the one closest to the firewall) and then to the glow plug relay

tbearatkin · Sep 1, 2010

beanman1 said:
ok ok here to the rescue that thing in the pic is the glow plug resistor. 24v power goes in and when the key gets turned on and the glow plug relay get energized it drops the voltage from 24v to 12v and lower but when a glow plug is bad it raise power to the rest of the glow plugs causing a chain reaction burning out glow plugs. If the resistor was smoking it went awol on you so what you need to do is bypass it or get a new one. To bypass it you need to disconect it from the battery junction block on the fire wall and from the glow plug relay. Then get some 10 gauge wire or bigger and run it from the negative terminal of the second battery (the one closest to the firewall) and then to the glow plug relay

Thanks today went to start it and all the batteries are dead. Has to be this glow plug resistor bank. No battery issues before and all I did was replace all the GP and then this resistor bank started smoking. Hopefully once I charge the batteries and bypass it I won't have any other issues.
Thanks
Bones

rlwm211 · Sep 1, 2010

It sounds to me like the glow plug relay stuck on and the resistors got hot. Glow plugs are designed at 6 volts operating voltage. By using the resistor pack and 12 volts, they are predictable in terms of timing, by using voltage rise as the glow plug warms up. As a heating element warms up, its resistance lowers.

That is why when you have bad glow plugs the circuit cycles rapidly because the voltage rises faster and the thermal timer trips quicker.

Check the glow plug relay and see if it is burned too. You may be surprised to find that it is actually toast.

Just my two cents worth
RL

xenocath · Sep 1, 2010

just to keep it simple make sure no glowplug wires are grounding friend of mine had that issue this week with the smoking resistor, it turned out to be a stupid wire

rnd-motorsports · Sep 2, 2010

If you need a resistor unit I converted mine to 12 volt have a good one will sell if you need one just removed from my 1028

tbearatkin · Sep 3, 2010

What is the easiest way to determine if the GP relay I have purchased is an internal grounded one or not. I see all kinds to discussion about make sure it is but no discussion on how I can check it to verify the part that was sold to me was correct. Thanks :roll:

doghead · Sep 3, 2010

What is the brand and part number of the relay you bought?

If your new relay has "s" or "i" labeling either of the small terminal, you have the WRONG relay.

To test whatever you have, use an ohm meter, and see if there is continuity between the mounting ears(metal frame) and either of the 2 small terminals. If there is no continuity, you can use it.

Did you search and read this? http://www.steelsoldiers.com/cucv/42044-gpr109-installed-gp-controller-card-hot.html

tbearatkin · Sep 3, 2010

Okay mine is good to go. Thanks.

I had Carquest cross reference NAPA ST85 and it crossed to their 56-2432. Box says it is called a starter relay. They also had a GP relay for a civlilan Blazer that did not look like the relay that came off. CQ 56-2432 matches in looks what was taken off. and looks like the ST85 that you had a picture of at that link. The CQ part number also was in their hard copy book as a GP relay.

Now with the engine running the relay chatters quits and chatters off and on about every 10 seconds.

tbearatkin · Sep 3, 2010

This is what the GP relay from CQ for the Civilian blazer looked like and is not the right part for these CUCV's

doghead · Sep 3, 2010

Should not chatter. It should snap on, and stay on, then off then back on( a few times possibly). If it continues to chatter after the engine is warmed up, you have a problem.

There is a troubleshooting procedure in the TM, follow it. You can diagnose every single component except the GP controller card.

MuleMac01 · Sep 3, 2010

where can you get a glowplug resistor pack. ? because mine did the same thing after i replaced the glow plugs also, smoking that is then my glow plug reley doest click on and off anymore

but the Wait light comes on and gos out

tbearatkin · Sep 7, 2010

I removed and tossed the resistor(see the last picture) and bypassed the 24V busbar with a battery cable to the neg post of the back battery. My wait light also would come on and go out but did nothing since the glow plugs were bad it was hard starting.

1. all glow plugs were no good so I replace them with the AC60A
2. glow plug relay was bad so I replaced it with a CQ 56-2432 (carquest)
3. resistor pack was bad removed it and used a 48" long battery cable to bypass the busbar to 12volts on the the battery.

No major issues since then minor issue windshield washer pumps fluid on the windshield when the wipers are turned on and no horn. Will trace these down

CUCV85 · Sep 7, 2010

napa st 85 or st 80 is = to AAP s603 much cheaper

tbearatkin said:
Okay mine is good to go. Thanks.

I had Carquest cross reference NAPA ST85 and it crossed to their 56-2432. Box says it is called a starter relay. They also had a GP relay for a civlilan Blazer that did not look like the relay that came off. CQ 56-2432 matches in looks what was taken off. and looks like the ST85 that you had a picture of at that link. The CQ part number also was in their hard copy book as a GP relay.

Now with the engine running the relay chatters quits and chatters off and on about every 10 seconds.

Napa st 85 is the same as napa st 80
= Advance Auto Parts BWD S 603 less $

CUCV85 · Sep 7, 2010

tbearatkin said:
I removed and tossed the resistor(see the last picture) and bypassed the 24V busbar with a battery cable to the neg post of the back battery. My wait light also would come on and go out but did nothing since the glow plugs were bad it was hard starting.

1. all glow plugs were no good so I replace them with the AC60A
2. glow plug relay was bad so I replaced it with a CQ 56-2432 (carquest)
3. resistor pack was bad removed it and used a 48" long battery cable to bypass the busbar to 12volts on the the battery.

No major issues since then minor issue windshield washer pumps fluid on the windshield when the wipers are turned on and no horn. Will trace these down

That 12 volt Diamond shaped Terminal Block
to the left and above the GPR works as well.
I used the right side wire including the Eyelet
from that Resistors block- :beer:

Saved money from buying that heavy gage battery cable you used.
Your way is bullet proof, but no War here so either way [thumbzup]

What is it and why did it smoke.

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