Grid heater stuck on...

[The patriot]

This morning, I started the truck and let it idle for about 5 minutes. As I pulled out, I noticed that my voltage was much lower than normal. When I reached 17 mph, the voltage didnt come up, as it usually would. (cycle heaters off)

2-3 miles down the road(@ 50+ mph) they finally cycled off, just as I was looking for a place to pull over.

Is there anything that "goes" in this system that I can check first?

Would this be covered under the powertrain warranty? I'm at 75K miles.

Thanks

Eric

 

[fest3er]

Originally posted by The patriot

... Is there anything that "goes" in this system that I can check first? Would this be covered under the powertrain warranty? I'm at 75K miles.

AFAIK, it is *not* covered under warranty; the relays are not part of the powertrain. The heater grids themselves *might* be.



Your problem is most likely the relays on the fender wall under the driver's side battery. DC price for a replacement set is about $70.



Mine have just started to want to fail again. This time I've ordered a couple Stancor relays that are similar and good for 100 amps continuous duty, at $15 each. It'll require a tiny bit of work to mount them, but they should fit just fine. I'm waiting for them to arrive, so I don't know more as yet.



I took my relays apart (carefully). The stud contact points inside still look good, and the contactors look good, too. But I think the springs that holds the contactors off the studs just get weak after time. And given enough time bouncing around, a bit of welding and melting happens, hastening the demise of one or both of the relays.



I *could* play with installing replacement springs (one in each relay), but I want functioning relays first, and I *won't* pay DC's price. I might still play with replacing the springs because the relays look good, otherwise. I'll post again once I have the Stancor's installed. And if I get around to playing with the springs, I'll post those results, too.



Fest3er

 

[The patriot]

Thanks for the reply Neal.

Let me know how that alternative relay works out.

Eric

 

[fest3er]

Originally posted by The patriot

Thanks for the reply Neal.

Let me know how that alternative relay works out.

Eric

I got the relays yesterday, modified the OEM bracket to mount them, and installed them today. They seem to be working just fine so far. They do seem to have a louder, more satisfying 'clunk' when they engage and disengage. (It's a diesel; noise is good, right?)



See http://murent.us/dodge-heater-relay/ for a modification drawing and relay sourcing info.

Original URL: See http://home.adelphia.net/~npmrphy/relay.pdf for a modification drawing and relay sourcing info.

To repeat some of the relay sourcing info, you need two Stancor 120-902 D. C Power Contactors. I got mine from Allied Electronics, (800)433-5700, for about $15 each.



These relays stand taller, so they may have a longer throw than the OEM relays, though I haven't taken them apart to see. Time will tell if they hold up as well as, or better than, the OEM relays.



One important note: since the relays stand taller, the coil control wires are a bit tight. Be sure you dress the edge of the plate and wrap the wires in some protective medium. Plastic split-loom works nicely. A bit of inner tube would also protect the control leads.



Fester

[Edit, 2/2/2015: These relays are *still* working like new.]

 

[The patriot]

Well, now that it's actually COLD out, it's been acting normally.

Thanks for the drawings Neal. I expect it to take a dump this winter.

Eric

BTW... who the hell is Ken?

 

[fest3er]

Originally posted by The patriot

... BTW... who the hell is Ken?

You find the answer in https://www.turbodieselregister.com/forums/showthread.php?s=&threadid=27631



And if you have to ask about the phone number, it'll be clear that you were off-planet for 10 years or so. Or maybe you were born in the wrong generation.



Fest3er