Advice about glow plug relay needed

[Mtrdrms]

I just got my fuel issue figured and wouldnt you know it, I ran into a glow plug problem. This is whats happening: My relay used to click and now it doesnt. I checked the voltage at the top post and it reads 24v. I checked the coltage at the two small posts and they both read 12v. The bottom post however reads 0. So, I replaced the relay with a napa GPR109 and the same symtoms are present. What do you guys think? I thought the bottom post should get 12v?

Andy

 

[appalacious]

Can you go over that again? Specifically the two small posts. What are you measuring them in reference to, etc.? You say they "both read 12V" and then you say the bottom posts "reads 0". I'm lost.
J

 

[Mtrdrms]

Sure. With the ignition on, the top post on my glow plug relay reads 24v. The 2 smaller posts between the top and the bottom posts each read 12v. The bottom (same size as the top) reads 0. Is this normal?

 

[doghead]

Not if the engine is cold and the gp's are cycling.

 

[Michael]

That is normal for a bad control card.

The relay is triggered by the control card completing the ground to the light blue wire. The plus wire stays hot all the time. Since it is just an electromagnet it will show 12v at both posts. You can hot wire the relay by jumping the light blue wire to ground.

The bottom post will show 0 when the relay is open, 24v when it is closed and no load (all glow plugs burnt out) and about 12 when triggered with all good glow plugs.

 

[Mtrdrms]

I see. Well I will try to bypass it and if that works I know its a bad card.

 

[doghead]

To bypass the controller, simply "jumper" the blue wire on the small terminal, to ground.(with the key on)

 

[Radioman]

I am expreiencing the same problem with my M1009. The under hood relay with the key on I get 24v on the top of the relay and 11.8 on the small posts. Grounding the blue wire does nothing to activate the relay. With the key off I can jump the top post to the small blue post and get the relay to work and start the engine. I would like the convenience of the original setup to work. I have been bypassing the relay to start the blazer for several years as it is not a daily driver. I am not interested at all in installing a manual button. Any ideas? Thanks.

 

[Michael]

I am expreiencing the same problem with my M1009. The under hood relay with the key on I get 24v on the top of the relay and 11.8 on the small posts. Grounding the blue wire does nothing to activate the relay. With the key off I can jump the top post to the small blue post and get the relay to work and start the engine. I would like the convenience of the original setup to work. I have been bypassing the relay to start the blazer for several years as it is not a daily driver. I am not interested at all in installing a manual button. Any ideas? Thanks.

Download the TM and go through the troubleshooting. You are feeding + 24v to the ground wire of the control card and I assume it is grounding through the + 12v feed. The card is bound to be bad. If grounding the blue wire at the relay with the key on does nothing then you need to find out if you have +12v at the other wire. You probably don't if you can get the relay to trigger the way you describe.

 

[Radioman]

I can only bypass the relay with the key off. I put a meter on the second small terminal with the orange wire and get .02v when I bypass the relay. I have three control cars from other m1009 and 1008's but all seem to have been burnt out. I have been able to fix all the others expect mine, figures, lol. I have worked on diesels for several years. Since this is mine it rarely gets my attention. Just pulled it in the shop last night to tinker with it.

I just registered here today. Not sure exactly where to find the TM but I will keek looking.

Thanks for your replies and help.

 

[Michael]

Cucv - Steel Soldiers::Military Vehicles Supersite

start with the -20. It sounds like you have lost the 12v feed to the relay.