Blazers dead, need glow plug help

[rizzo]

I just unplugged the temp sensor (made it an open circuit) and still no "wait" light or GP cycle sounds.

I checked all the fuses under the dash and did not find any blown ones.

what is my next step?

 

[CUCVFAN]

When you jumped the solenoid, did it actuate (click)?

With the temp sensor unplugged (open circuit), the GP's will operate as if the engine is cold.

You can test the card/bulb by unplugging the module and jumping the dark blue wire to ground in the connector. Turn the key to run and the wait light should come on. If not, the module or bulb could be bad.

 

[rizzo]

When you jumped the solenoid, did it actuate (click)?

yes it did

With the temp sensor unplugged (open circuit), the GP's will operate as if the engine is cold.

so if the light doesn't come on with the temp sensor bypassed it might be the light.

problem is even with no light the GP's are not cycling.

You can test the card/bulb by unplugging the module and jumping the dark blue wire to ground in the connector. Turn the key to run and the wait light should come on. If not, the module or bulb could be bad.

I will do this

thanks for the help

 

[mangus580]

Rizzo, check the condition of the wires at the temp plug.... mine were in bad shape and pretty frayed, and could have been touching...

 

[rizzo]

Is there a fuse for this system??

I couldn't find the schematics in the TM. do yo know where it is?

 

[CUCVFAN]

If you jump the relay and it is cycling, you are bypassing the controller system altogether and there is nothing to prevent the glow plugs from operating, except a bad resistor pack. Check the voltage there (unless you are already pulling the voltage from the 12V junction).

There are 2 20-amp fuses that affect operation. I believe they are the top two on the left side of the fuse block, but I would check the voltage to the hot side of the relay first.

 

[rizzo]

when I jump the dark blue wire to ground and the the light came on. When I took the card out I saw a black mark on it. looked like some sort of electrical blow out.

when I jumped the light blue wire by accident it started the relay and I had power to the plugs.

I think a bad card is the problem. I'm curious on how to trouble shoot the temp sensor. do the wires for the temp sensor go to the card?

comments or confirmations?

Mike the wires are old and crusty, but don't look worn

 

[ida34]

Check in the -20. On page 2-62 there is a pin by pin check of glow plug items that you can check at the glow plug module connector. This will pinpoint exactly what is wrong with you. It gives the wire color and what value you should see. Then it gives you what is wrong. Also, the schematic for the glow plugs is located at figure F-7 and F-8. If you are viewing the -20 with adobe you can check the left side of the screen. Open the figures section then chose the above listed ones. On page 2-62 there is a click-able link to the schematic.

Also note that the relay can still click and be bad. The one on my new cucv was like this. If you need anymore help let me know and maybe we can work something out on the weekend. I think the flow chart on 2-62 will get you going.

 

[CUCVFAN]

The wires from the temp sensor go to the card. The yellow wire and the black next to it should be the wire to the sensor, according to the manual.

If the sensor fails open, the glow plugs will operate even when the engine is warm. If it fails closed, they will never operate.

 

[rizzo]

Thanks guys. I have been reading the TM and understand it. I think I will perform a few test tomorrow to confirm that the card needs to be replaced. I think I read in another thread that it cost about $125.

 

[CCATLETT1984]

Thanks guys. I have been reading the TM and understand it. I think I will perform a few test tomorrow to confirm that the card needs to be replaced. I think I read in another thread that it cost about $125.

Unless you are dead set on having it remain stock from the military, just do what a bunch of us have done and change over to a manual GP setup. Then you just hold the button until the "wait" light goes out.

 

[CUCVFAN]

Thanks guys. I have been reading the TM and understand it. I think I will perform a few test tomorrow to confirm that the card needs to be replaced. I think I read in another thread that it cost about $125.

Last time I checked, it was available at GMPartsDirect.com for about $85, if I remember correctly...

 

[mangus580]

www.flmv.net has them as well..... although Not that cheap..

 

[CUCVFAN]

www.flmv.net has them as well..... although Not that cheap..

Front Line is selling the harness and module, according to the NIIN they list. GMPartsDirect only has the module that you plug into your existing harness. Better? If your harness is OK, you bet! But, if you suspect that some wires are funky, replacing the harness might not be a bad idea...

 

[CUCVFAN]

I just checked GMPartsDirect and their shipping is outrageous!! $18.90 shipping on that card!!!! Their policy is a minimum of 22% item order total!!!

Still, it's only $105, but I'd probably just buy the harness and module from Front Line. Their shipping has to be reasonable.

 

[rizzo]

the dealer has them for $144 and no shipping

part # 12034592

 

[CUCVFAN]

Yeah, that's the list price. Do you know any mechanics or body shop guys that can get you a discount?

 

[rizzo]

Yeah, that's the list price. Do you know any mechanics or body shop guys that can get you a discount?

I didn't think of that.

I ordered it from GMparts and saved $40 bucks.

 

[CUCVFAN]

Agreed, it's still a good deal. It justs frosts me that they rip you that bad for shipping...

 

[ida34]

I got one at the Clare Michigan show from one of the vendors for $45. Works great but can't find deals like this everyday. I was lucky enough to still have one in the newest one from GL.