So i've had a few grid heater issues latley and have a few questions.

I had what I think was the Grid controller box take a dump and I lost all grid functions and the speedo. I replaced the controller and the speedo came back but I still don't have any preheat, after the motor fire I have post heat but no preheat. Is the control box still the culprit? It was a used one I put on out of an 89.

 

One thing Andrew. The 89 you got it from would have had a cable driven speedo. How would that be hooked to your speedo circuit? Also 89's had 2 different controls. Early, and late. I think it was just the settings that were different.

 

Well i thought it was an 89 I got it off of, I'll have to ask Mark. I new ther was an early and a late control box. The early one wouldn't preheat unless it was 32 or below and the late one would preheat at 59.

 

The early one won't preheat til 15*F!!

 

Bill, that still doesn't explain why I have post heat though.


I might try another box and see what happens.

 

Post heat is emissions related, I would fully expect you to have it at a much higher ambient temp. than the starting aid heat.

 

Kids. You have an early module. Won't preheat til 15*f. But will post heat. That's how my early 89 does. You have a good working module. Get a bigger battery, better starter, air tighter fuel system, better charging system if you have issues starting with that module.

If you searched hard enough, you'd find the module serial number break between the early and late units.

 

bypass the controller, if you dont want to mess with compatibility, just manually switch the relay for a few seconds, it will be enough to start

 

Looks like I'll have to find a late module again. I can see why Dodge went with the late module now. My truck starts alright as i have a new battery, rebuilt starter, and a charging system that is top notch, and an air tightish fuel system but I don't like cranking on it for 30 seconds to get her to light and when it does light off it pops and farts and smokes about like I do in the morning.


Patdaly, this thing starts post heat as soon as it fires and cycles normaly.

 

check car-part.com look for a salvage yard with lots of cummins, by year/application, they post phone numbers with parts available.

 

On mine i ran a fused hot wire to a push button momentary switch on the dash ran from there to the solonoids to activate them they are relays so it takes hardly any power to activate them . Below about 35 or so i hold the button a few seconds at about 8 below held it about 15 or so fires right up without hesitation