M1008 resistor

[romistre89]

I am getting almost 25v at the relay and the glow plugs, I'm i correct in asuming the resitor is bad, and if so does anyone know where I can get one. I would like to replace this rather than go to manual. any help?

 

[FMJ]

It should be around 25 volts, then drop slowly.... Are you using the stock wellman plugs?

 

[mangus580]

Are you measuring this while the relay is on, or off? It would be an accurate voltage with the relay off. Wit it on, you will measure roughly 11.5 volts with 8 good glow plugs. Anything higher than that you most likely have faulty plugs.

I just went through this helping a fellow member with his glow plug system. Its the first time I actually put a meter on the system in that fashion.

 

[roberbert101]

i have a old resister i took off my truck when i converted over to 12v if i can find it it was working. let me find it see if yours is bad, if so il give it to ya

 

[85-m1028]

I thought the resistor should read like 3 ohms across it right?

 

[mangus580]

I am not sure on the resistance... I just know what the voltages measure.

 

[ida34]

The voltage drop is based on the load of the system. Without any load it will allow the full voltage through. The volt meter does not provide enough of a load. It has already been said that if all the glow plugs are working then under load you should see around 12 volts. If the electrical load goes down as in when a glow plug burns out then the voltage raises. I had a wire come off one plug. After a few weeks I ended up with three bad glow plugs. The disconnected plug allowed the voltage to rise the other seven. As soon as one burned out the voltage when up and took out another pretty fast. This is why we see a lot of trucks with all the glow plugs burned out. The voltage keeps rising and it creates a snow ball effect.


You say the relay has 24 volt and the glow plugs are seeing 24 volts. If you have 24 volts at the plugs then something is wrong.

 

[mangus580]

Chuck, he never did say the glow plugs were getting the 24v. Thats why I asked at what point he was measuring the voltage.

 

[romistre89]

the plugs themselves are seeing 24 volts with the relay cycled on or off. I put all new ac delco 50g's in it and it started fine for about four months. Then I thought maybe the ac plugs weren't good enough and ordered well plugs and every one of them are dead. I got them all out (alll slightly mushroomed), but I want to figure out this high voltage problem before I burn up another set of plugs. The card is cutting the relay on and off and the relay is not sticking I am just getting 24V through the relay and to the plugs whenever the relay is on.

 

[mangus580]

what was the last plug you had in there? Was it Wellman 070? Did they have the narrow spade connector?

If you use the wrong plugs... they will fail prematurely.

Put in a set of the correct plugs, and upon the first time you use them measure that voltage. That will tell you if the resistor is bad.

Its highly unlikely that the resistor would fail in such a state to allow full voltage through.

 

[romistre89]

I pulled the resistor off the wall ohmed it from the nput to the output and got no resistance, actually i got true continuity.

 

[romistre89]

they were 070 with thin spades. I got them from INDUSA. they said they were the exact ones the military used

 

[romistre89]

posts not posting lets see if this works

 

[romistre89]

rtj

 

[mangus580]

I guess the resistor is bad then I really dont see how, unless the insulator failed, and wires are touching

 

[mangus580]

Common bypass is to just move the wire from the output of the resistor to the 12v terminal on the block right there.

When you do this, you wont be able to jump it using the slave port, if your batteries are totally dead.

 

[romistre89]

my posts are not showing up ?

 

[mangus580]

I see a bunch... last one says 'rjt'

 

[Crash_AF]

Ditto, I see them too

Later,
Joe

 

[romistre89]

Ok now that I figured this out (look at page 2) one last question. Can I run a 10 gau wire straight from the negative post of the battery closest to the firewall (this is 12v) straight to the relay and still have the card control the plugs, totally bypassing the resistor or will this disrupt the function of the card?