Just wondering if anyone noticed their grid heaters coming on after engine has warmed up? Mine will turn on and cycle 4 or 5 times when warm with no wait to start light at that time. I checked all the sensors and they are all reading correctly. Outside air temp around 55 F

 

Yes, it happens. If the ambient temp fall below... I think it may be 50, not sure, they will kick on to heat the intake air. This can occur while driving, up until 25mph (I think that's the speed). I can look up the exact specs if you want.

Nothin's wrong. As long as it does not stay on, you're good.


hth... I know the actual facts are vague... but you get the idea...

 

I think I heard it was 60 degrees F but I am not near my truck to check.

 

18 MPH they go off.

outside air temp under 45 cycle even if engine is warm.

intake temp over 60, and outside air over 45, no cycle at all.

 

thanks Timmer and everyone for your input, that's what I thought, after checking all the sensors, which were within 1 degree of each other. Ecm would still cycle the preheaters on with engine at operating temp and outside air temp at 60. I'm thinking ECM, I will try new ECM tomorrow.

 

BigIron, mine cycle when it is well over 45 OAT but it has to be somewhat cool out (they won't do it when it is 65 degress).

I don't really care. I'm still trying to figure out why my interior lights shut off after 10 seconds.