2005 Super M Series 2 Grid Heater Relay seems to be inop.

[onehandman1]

Hello All,

It seems my grid heater doesn't work. Hard starting when cold. The only time i see the glow plug light is with initial key on. What my testing has done for me... in a heated garage 62F the temp sensor on top of engine 2500OHMs(i believe this is good). Wiring ohmed out from sensor to the "module". The relay works. Clicks when supplying 12V to it and it connects the high voltage side. The "module" has 12 V and ground going to it back probed with a DVOM. It also has a "good" ground. Measured ground by checking continuity (I know this isn't the best way and it should be load tested.) I never get 12V going to the heater grid relay. I believe the iveco heater grid "module" isn't working properly, but wanted to make sure I didn't miss anything silly. I can tell the previous owner of the machine was also trying to diagnose as many of the connector locking clips have been broke related to the heater grid system.

Thanks in Advance.

Paul

 

[JL Sargent]

I'm not familiar with that module, but a temporary work around might be to connect the grid heater directly to the battery for starting until you get the electrical circuit for it working properly.

 

[onehandman1]

JL, I thought about wiring in a timed relay, but fortunately it is maintenance season for the ol girl and she'll sit in the barn until its spring time. -2F here this morning No need to get cold!

 

[melben]

I worked for a Case dealer for 50 yrs and did factory updates on the grid heater relay board. I made up a cheater to force the board to work even with the engine warm. The cheater was a 1500 ohm resistor epoxied into one the the red injector tip protectors with the lead spacing fit to slide into the harness wire terminal for the grid heater switch, I am suspect of the ohms reading you have as 1500 works to hold the system in operation. If you could come up with a resistor for test purposes it may be helpful, Just plug it in the harness and see if it locks the grid heater on when activated. You did not say how long the grid heater light stays on, they do time out.

 

[onehandman1]

Melborn,

Just to clarify the heater grid switch is on top of the engine( this is what i came up with looking through the manuals). I'm sure I can get a 1500OHM resistor. The light illuminates in the cluster for 5 seconds or less. When it does come on, I never get 12 V going to the heater nor do I get 12V going to the solenoid to actuate the heater. Is it fair to assume, these should work under 50 degrees?

 

[onehandman1]

Just wanted to let everyone know. New heater grid module = problem solved!