GP relay stuck on

[V8Astro]

I had my '08 at work last week to replace my brake hoses. Why did they spec DOT 5 brake fluid? $$$$$$ OW!

I got distracted at one point and bled the master cylinder dry. After I refilled and bled the air out AGAIN I went to refill my brake clean can. When I came back there was smoke rolling out from the back of the engine compartment. I immediatly thought "oooh sht I left the key on"! I ran to the cab and found the key sitting on the seat. I ran around again and disconnected the front battery ground. Then I blew shop air on the resistors to cool them off. No fuse links melted.

After some poking around I wacked the GP relay with a wrench and heard the clack of the contact disengaging. I can't imagine the damage this would have done if I had parked the truck at the store or something and walked inside. Whew! Of all places it did it at work with my fully stocked tool cart near by.

I pulled 2 glow plugs and the tips looked a little blistered. Kinda like when you heat steel too hot with a torch and it turns dull gray and flakes. That's a real bummer since I just replaced all 8 a couple months ago.

Just had to vent. I almost had a heart attack...

 

[doghead]

Is your wiring all stock? What relay is installed in your truck? I recommend rewiring your GP supply to 12v. If it happened once, it may happen again, unless you find the issue. I would at least replace the relay.

 

[V8Astro]

I replaced the relay with a BWD S55. All wiring is stock. I prefer that the GP system pulls from both batteries. If I convert it to 12v it runs off only one, correct?

 

[doghead]

Yes.

You realize with it stock, all GPs will typically fail, when one fails?

If you supply with 12v, that is not the case.

To each his own.

I wonder if that relay is somewhat position dependant, to function correctly. I wonder what amp and duty cycle it is.

I think I would replace it again. Sometimes considering only initial cost, bites you in the butt.

 

[V8Astro]

I should have said in the original post that it was the "OE" relay that failed. I search the forums to get that BWD part number, and then replaced it.

Thanks for the help. Is there any way to rewire the GP system so that it pulls from both batteries in 12v? Wired in parallel maybe? I don't have the wiring diagrams in front of at the moment...

 

[doghead]

Not easily or cheaply or reliably.

Ok, if it were an original(25 years old), I can accept failure with no apparent reason.

 

[V8Astro]

One more thing while you're here....

I have 8 AC60G glowplugs but am still running the 24v supply with resistors. I got the glowplugs before I joined this site. Is this going to cause problems further down the road?

 

[doghead]

Yes and no.

AC60G GPs will work just fine.

Just remember, with the stock 24v feed through the resistors on the firewall, when one GP burns out, the voltage will increase, causing the rest to burn out. That's the bad thing about a stock GP system.

If you resupply the GP relay with 12v, when GPs burn out, you'll simply have decreasing performance while starting. It takes about 5 minutes and 50 cents, to convert to 12V GP supply.

 

[DriverSideImpact1008]

I second and third what DH said. Just do it. It's so easy it's stupid. Even if you totally remove the resistor and all the wiring it still only takes about 10 minutes.

I have AC 60G's in mine with the bypassed resistor, and an ECH GP109 relay and it starts great. Takes between 10-15 seconds to cycle the plugs in 20-40°F temps. Which seems pretty normal.