Grid heater relay

[Joe176]

I have a 2006 5.9 Cummins ... it has a single relay grid heater ... when key is turned on check engine light comes on instead of heater light ... I had power going into relay from battery but no power coming out from relay to grid heater ... installed new relay and still the same thing ... checked for fuse but owners manual doesn't ID which fuse it would be and cannot find any blown fuses ... any ideas ???

 

[lpennock]

What is temp? Relay doesn't come unless it is cool enough.

 

[SnoKing]

I think it is activate on the ground side, not the hot side?

Do you have a code set? P0541? SnoKing

 

[PWong]

I had power going into relay from battery but no power coming out from relay to grid heater ...

How many wires on the relay got power???
One big wire should always has power coming the battery positive post. One skinny wire should get power when key ON and the ambient temp below 66F.
After that you check for power at heater elements.

 

[PWong]

The big wire is the DG wire on relay-30, power comes from a fusible link. The skinny is the BR/YL wire on relay-85, power comes from ECM (Intake Air Relay Relay Control signal).

Relay-86 (BK wire) should be grounded.
Relay-87 (BK wire) sends power to heater element.