nick, 2001 is the same, look at your service manual, page 8W30-35 for the GH schematic, shows ground thru S109 shown on 8W15-11 Ground schematic.

Somehow you are grounding it to the PCM............

If you think about it, with a 12V applied system you would NOT isolate it from ground.

EDIT: Man, I must be in need of more caffeine. Nick is correct, obviously if the other side of the GH is connected to ground, then the PCM must be providing the 12V to the GH.

Leran something new every day here, anyone for sure when they made the change from grounding to voltage applied?

Thanks guys.

 

1 just pulled off all 4 wires hooked up 2 grds and two to switch,no chance of bad feedback to comp.

 

Read and learn.

http://dodgeram.org/tech/dsl/trouble...diagnostics12V

 

Thanks Guys and Thanks nitrousn for the link
I will check this out tomorrow morning, try and hook up a switch and will report back
thanks again

 

Mine is an 01 and as per nitrousn's post mine is energised with a + signal, NOT via a ground, for mine when you use the orginal mounting plate with Ford solenoids there is no ground because of the rubber grometts isolating the mounting plate from the truck, I ran a ground wire to the plate and interupted it with a switch so I could disable the grid function, as I have the problem of it cycling the grids on EVERY start (it can take up to 2mins to stop) so its very hard on the charging system and the risk (happened to me) of having the grid relays stick on, killing the batterys

 

I understand the risk, but if the IAT sensor is telling the heaters to run...shouldn't they be running? Just asking because I have no experience with the Cummins in very cold weather.

Anyone up there with an Adrenaline? I'd be interested in what you get for an IAT readout, with grid turned off, after startup.... if not plugged in.
On a 20*F morning I get about 90* IAT after startup... but that's with grid heaters. Below that IAT and my engine runs very rough for a while.

RJ

 

RowJ, I am almost certain any after start GH operation is simply to reduce emissions.

 

like RowJ said, can a bad or full of soot IAT tells the grid heaters to stay on much more? i tell this because on my 99 it stay on more than 30sec sure...and here isn't so cold never below 0° Celsius now.

rob

 

has anyone actually used a watch and timed prop. working heaters in cold temps -20

 

I've instaled a new IAT, no change, I have an attitude monitor and will watch the IAT's to compare them..Its more of an emissions thing. actually If you have seen the inside of the stock relay you'd wonder how it doesnt melt down

pic's comming

 

There is a good chance that using a different solinoid that you burned up the solinoid drivers from the factory ecm. Like I said a good chance. Reason I say that is the ecm is very delicate and designed to supply minimal out put. Not knowing the amperage draw to close the ford solinoids v/s the factory solinoids could very well do damage. It may be worth checking into. With electronics one should never gamble unless you know the facts. Just because they worked does not mean they will be working for the long run. I know the lift pump drivers will get fried if you use a heavier draw pump or stack two pumps.

 

good points! Something to research for sure, I'll work on it

Here are a couple pics of the grid relay internals, note the very small contact patches

 

It appears that the post start grid cycle is based on the ambient air temps when the engine was started. I have watched the intake air temp and it appears to have no effect on the post start grid cycle. It will effect the fast idle/3cyl idle function without another device like the Adrenaline controling the fast idle.

It appears there is some grid cycle (both pre and post start) at any outside temp below 70 deg. Even with the engine fully warmed (only shut off for a few minutes) , IAT reading 130 deg at start, the grid cycle will happen. I also susspect that the grid relays are controled independant of each other although, I have not monitored them both at the same time to verify this. Once started, the cycle will continue for 2 minutes or until speed reaches about 19 MPH.

I also had a grid relay fail and stick on. I just shut off the truck and unplugged the small wires from the relays until I could replace them. It seemed that once mine applied, they could not release but would disengage when I shut off the truck.

 

It would be good info if one could get the activation coil winding amperage draw to see what the oem draws compared to the ford.

Those oem solinoids do get a pretty good work out. They most likely get 2 to 4 times more activation than a starter solinoid. They aslo have a fixed draw where a starter has a varible load and a heavy surge load on the initial cranking. Thats why the heated air solinoids seem to last longer. Like anything else they can fail.

 

RacerRon
I did test mine and they do alternate grids, confirmed with a test light on both grids, usually a relay sticks on the hi amp side, which is what happened to both of mine, you were lucky (or unlucky depending how you look at it) as the ECM must have been holding them on. I think for the interm I'm going to unhook the ecm's control of the grids and wire it to manual push button control. My truck is parked in a heated garage and once its started to runs 8-9hrs a day. so my need for grids is pretty limited....but with manual control should I need them I'll have easy access.

To the orginal poster sorry if I've hijacked your thread