Glow Plug Resistors smoking?? Help.

[82ABNMP]

I did ssearch but could not find an answer to my issue. So here is the problem,
The truck was not on the glow plug system when I got it, someone had by-passed the GP resistors with a hot wire to a switch inside the truck. So I am putting it back original. It has new repo GP card, new AC 60G plugs, new doghead starter mod, new ST85 relay. After all the new stuff it fires right up...but it seams the GP relay hot wire (red wire on top) continues to draw power AFTER the truck is turned OFF. Volt meter reads 12.5 when motor is not running (on the top red wire) and the key is off!!!? The resistor wires start to smoke!! And the front battery pos terminal is drawing power in the off position? Ideas please? Sounds like a short but where??

David

 

[Warthog]

This will require some testing.

Disconnect the resistor wire and see what happens. It could be that the resistor pack is bad and has a short somewhere.

When reistalling the GP relay, where did you install the small orange wire?

 

[82ABNMP]

GP

Hey Joe, thanks for the help again.

I did test the resistor wire..I took it off the wire block and left it on the top post of the GP relay. Tested it for resistnace ohms, it was .4

I understand the GP relay top post should be hot with 12.5 volts in the off position.

Here is a picture of the current connections. Small orange wire is ont he bottom post of the GP relay.

Thanks!!!

 

[m38inmaine]

If it is the original configuration the top hot post of the relay should show 24v off, 12v in the on position if the relay is energized and providing power to the glow plugs. The resistor bank is fed from the 24v block on the firewall behind the rear battery. Once power is applied to the glowplugs the 24v is reduced to 12v as a function of the resistor bank. The only time you should see 12v at the top relay post is when the glowplugs are activated.

 

[82ABNMP]

GPs

Ok, did some more testing. The top post of the GP rellay is showing 0. with the key off. If I am reading it correct. And the resistior wire at the wire block is reading 0 with the key off.

So it (top post of GP relay) should read 24v with the key off?

 

[Warthog]

Okay here is your next test.

Sounds like the fusable link for the GP relay was what smoked and not the resistors. (since you said you had Zero Volts)

Yes with the key off you should be seeing 24v at all times on the top post of the GP relay.

Here is a picture of which wire to check.

 

[82ABNMP]

GP

Correction!~ I had the meter set wrong.....the top pos of the GP relay is 24.9 off and the wire at the block is 24.9...so that good.

The problem happens when I go to start the truck, the truck starts great but then the resistor starts to smoke, and the pos wire from the front battery to the resistor wire gets hot and the restor wire also. Then shut the truck down and the GP top post is still drawing volts from the front battery (wire is warm) Disconect the battery cable and it wants to spark. Once it's disconnected (battery) and reconnected the problem is gone. (wire cools down) thanks, it's hard to explain.

 

[82ABNMP]

relay

Hey Joe, I did check that wire and it has 24.9 in the off position. The wire is in tact and the fuse is not broke as far as I can tell. I am pretty sure it was the resistors as the smoke was rolling out from behind the resistor shield. I will check again.

 

[Warthog]

The fusable link is fine.

From your latest description, the GP relay is staying engaged. May be bad or there is a problem with the small wires on the relay.

The pink one supplies 12v and the black is the ground.

Remove the ground (small black wire) and make a jumper wire to reconnect it. Use this wire to test is the GP Controller Ground circuit is bad or not.

 

[82ABNMP]

Self inflicted wound

Ok, I found out the issue...ME!!!

Joe, is the master and correct on the last post.

The story: ( I almost did not re-post due to the embarrassing nature of the idiot behind the wheel) I am preparing to paint this truck and in the process installed a new manual GP switch, so yesterday I was taping the truck and taped the manual switch before paint...but I did not try to start the truck until this morning, so when I went out to start the truck today (with the taped manual switch closed grounding out the GP relay) when I turned off the truck the GP relay was still grounded...and drawing volts!!! Once I figured this out I took off the manual GP switch and was going to re connect the batteries but they were shorting out....you guessed it I fused the GP relay and it was shot! So I installed a new GP relay reconnected the batteries and it works like new.

Operator error!!!!!!!!!!!!

Thanks for the help! The folks on this site are GREAT!!

David

 

[MakersTeleMark]

I had a bit of a similar problem when I installed my glow plug manual override. Turns out, the momentary switch I bought from NAPA was cooked. It apparently couldn't handle the amps so was always grounding the circuit. Put in a heavy duty one from Grainger and it works like a charm.

Thanks for posting up your findings, oftentimes, threads like this just die a frustrating death.

 

[82ABNMP]

Everybody happy again!

Thanks from all the daughters.

 

[doghead]

Even the dog looks happy now!

 

[southdave]

Thanks from all the daughters.

Crap how much TP you use in a month??
I have two and a GF and there usage justifies a Sam's club membership once a month... I feel for ya

 

[combatmech]

Good catch David....at least you didnt throw gobs of parts and money at it. Was it the pick-up??

 

[82ABNMP]

Truck & TP

Ben, it was one of the other M1009's, yeah at least it's fixed and I know what happend.

I have 4 daughters and a wife, female dog, female cat....

TP is usage is one Sam's club brick every two weeks! It's the cost of the shampoo that is freaking putting me in the poor house!!!!!!

Oh well oldest daughter is on the way to college at Wake Forest U. in the fall maybe that will help....NOT!!!

 

[frodobaggins]

Thanks from all the daughters.

You see, this man is smart. He has figured out a way to have endless lines of teenage boys come over to his house that he can press into service unless they want to stay home. Free labor

 

[combatmech]

Still loving the new paint job David!! Havnt had a chance to get it dirty yet.
Guess I'm lucky, only one daughter.....that is out of the house!! For now....

 

[UncleSam]

Thanks for posting those pictures. I'm also want to put the glow plug relay back to original. The pixs help me to see whatswhats. I have two wires cut and I see that one of them from the resistors on the fire wall, I need to get a fusible link wire and connect it. But the other wire that is cut is a red wire coming from the wiring harness on the fire wall, I think it would connect to the jumper wire that the manual push button is connect to.
Thanks Again,
Uncle Sam

 

[OL AG '89]

HOLY CR*P
4 DAUGHTERS.......
I have one (out of the house, but still on bank of me..... looking for HIGH PAYING COLLEGE GRADUATE JOB)

You NEED this hobby to maintain the testosterone levels
but you also get to explain to the "new" boyfriend about lack of FEAR in going BACK to prison......LOL