Is the glow plug temp switch the same from cucv to humvee?

[ida34]

I think I need to replace the temp switch for my glow plugs. It is the one located on the right side of the engine in the rear. I know it is a military only item but is the same sensor used on the Humvee. I have a Humvee engine in a box but it is alot of work to open it up only to find it is a different setup. Can someone tell me if it is the same switch. I am at work and have slow dialup or else I would check the humvee manual.


Thanks
Chuck

 

[mangus580]

RE: Is the glow plug temp switch the same from cucv to humve

Not sure, but i have to replace mine too I do know that www.flmv.net has them, but they are about $40.

 

[gasser]

RE: Is the glow plug temp switch the same from cucv to humve

I got one from FLMV; it had a different 'newer' connector on it with a instruction sheet on how to change it (wires match up, etc).
I don't know if went to the Humvees 6.2s, but the connector on it was a newer GM style.

HTH,

-graham

 

[emmado22]

RE: Is the glow plug temp switch the same from cucv to humve

humvee uses the round rubber military style plugs on the sensor, and just about everywhere else.

 

[dilvoy]

Ida34, the switch located on the rear of the right head just rearward of the exhaust manifold is the Cold Start Advance Switch. The CUCV and Humvee both use this place for this switch. The Humvee switch has the water proof connectors as mentioned by Emmado22. The glow plug temp switch on the CUCV's is located on the rear end of the right head. It is in the special coolant crossover block off plate that has threads to accept the bushing and then the temp sender. The Humvees don't use this same switch.

 

[n1vbn]

The HMMWV is 24 volt through and through. The CUCV 24 volt system is the slave connection, one starter relay under the dash, the volt meter on the dash, and the starter motor. Everything else is 12 volt (excepting the M-1010). You should be able to find the part at your local auto parts store or your local Chevy/GMC dealer.

 

[ida34]

The switch in question does not care about the voltage because it is a variable resistance switch. It just sends different resistence levels to the control box under the dash. The civy switch is the controller on the civy trucks so this switch is military specific. This one had two terminals and the one for civy trucks has many more as far as I have seen. I realy am not sure the sensor is out of spec. The manual said that you should see at least 800 ohms when the engine is cold. Mine seems to be at about 4000 ohms cold but it does not seem to change as the engine heats up. This is the only thing that leads me to believe that the thing is messed up. I just put in a new used controller board. When it is cold the wait light comes on but the glow plugs are not getting juice based on the readings from the volt gauge and a test light on the relay. The wait light goes out after a few seconds. Not nearly enough time to start the engine when cold even if the plugs were getting power. None of the components on the board seem fried. Anyone else have this problem? I hate to blindly replace stuff without being sure it is bad.

 

[dilvoy]

Ida34, if you look at the schematic of the cucv glow system, you will notice that the glow plug relay has two controlling wires. They are the small ones. One is blue and one is orange in color. The blue wire leads to a ground somewhere. I had a problem with a cucv and when I grounded the terminal with the blue wire, everything started working normally. The glow light would stay on the normal length of time and everything, so I just ran a ground wire to that terminal and everything has been good for two years. This may be one of the things that leads to cucv glow fustration. There must be a way to find where this errant ground connection is, it's probably up under the dash somewhere, but my fix is still working and I have not butchered any wires to do it, so I'm satisfied. Maybe you are having te same problem.

 

[ida34]

The blue wire is the trigger from the glow plug control board. The hot wire to the relay should be hot when the key switch is in the on position. When the controller board wants the glow plug on it supplies ground to the relay. If I ran a ground wire to the blue wire terminal my glow plugs would stay on all the time. I am not sure what you have going on but someone has modified it.

 

[dilvoy]

That's interesting, I haven't had any low battery problems and I let the truck sit for a week at a time. I would think the glow plugs would draw the batteries down within a day. I'll have to check for wire harness butchery.

 

[ida34]

When the key switch is off the positive current to the relay is interupted so the glow plugs would just be activated when the ignition switch is in the on position. The -20 has a very good outline on what every terminal does under the trouble shooting section. It sounds like someone bypassed your system in some way. Do you have the controller board under the dash near the column?

I forgot to mention that my bypass of the Controller involves a switch that provides ground to the relay at the blue wire. I do notice that the glow plugs do not immediatly go off when I release the switch but they do go off after a second or two of the truck running. When I try to start the truck the wait light comes on and I check the volt meter for a change. There never has been one so I hit my bypass button. I can hear the relay engage and the volt meter confirms the current draw. When the seatbelt light goes off I release the button and start the truck. The volt meter still shows a draw when the button is release and for a few seconds while the truck is running. After this the volt meter comes back up showing the glow plug draw is gone. The wait light is on for longer periods when it is cold but the relay never engages until I hit the bypass button.

 

[dilvoy]

I'll look under the dash tonight. The card is in it's place hanging near the steering column and the glow light only comes on for cold starts and shows no current draw on the gauge after a minute or so. I had looked around prior, looking for loose or spliced wires, but found none. Now i'll take a closer look. I may actually find the original glow plug relay ground unplugged. That would be nice.

 

[ida34]

From what I saw the ground comes directly from the glow plug controller card. When you look at the card check the terminal from the temp switch and see what resistance you get at what ambient temp. I think it is the yellow wire but I will check again. When I hear of other people having fried controller cards they have said the component on the card was visibly fried. None of the components on my card seem fried.

 

[dilvoy]

ida34, well..... I thought I was a smart feller, but I guess I'm just a fart smeller, because when I got home tonight, I put one of those cheapo christmas tree light alt testors on my #1 alt and started the truck and noticed that the alt was putting oout only 12.5v at idle. The second I snipped my "new" ground wire, the entire christmas tree lit up to 14v. The glow plugs must have been, like you said, running all the time. Now I'm back to my flickering Glow light. I haven't tried to start it, but I bet it won't power the glow plugs. I guess I'll have to find where the ground is in the glow system. The card looks fine with no burnt places and I tested the vehicle with a known good card back when my problem appeared. Back to the drawing board.

 

[CCATLETT1984]

do a search for our bypass moifications. just run that blue wire to a switch and then ground the switch. that way when you press the switch it will complete the circuit and the glow plugs will get juice. I hold mine until the wait light goes out. then when you release the button it interupts the circuit and the GP's don't get an juice.

 

[CCATLETT1984]

I just hope that you didn't burn out your GP's, if the swelled you could be pulling the heads in order to get them out.

 

[dilvoy]

ccatlett1984, Back when all this problem started about two years ago, I was having glow plugs only last about a week. After three sets, I suspected the Resistors, so I bought a set of civi self regulating glow plugs and wired 12 volts to the relay. worked great for a year until I started getting a flickering wait light. That's when I found out that the ground for the glow plug relay was not good. Tonight I made my own temporary on button bypass setup and it worked great and the civi glow plugs are still going strong. I just pulled the glow plug card out for now. Those things must have had power going through them for about five thousand miles of travel. I find it almost inpossible to believe that they still work, but they do. Self regulating is the way to go I guess. For a while I must have been Paramor's best customer for glow plugs.

 

[CCATLETT1984]

I have the self-reg. plugs too, did the same thing with the resistors.

I had an issue with the GP card in mine and it ended up bieng a small transistor. its the voltage sensing chip. located near the top of the card and it has three contacts going to the board. I have several spare chips and I you like I can mail you one. the controller card should still work having the 12v going to the plugs.

 

[mangus580]

BTW, the glow plug manual setup, as well as a civvy contoller setup are both in the Tech article section.

 

[ida34]

I have the self-reg. plugs too, did the same thing with the resistors.

I had an issue with the GP card in mine and it ended up bieng a small transistor. its the voltage sensing chip. located near the top of the card and it has three contacts going to the board. I have several spare chips and I you like I can mail you one. the controller card should still work having the 12v going to the plugs.

What were your symtoms when the chip went bad? Does it sound like what I have going on?