1992 Cummins. Issue started last month at minus 20 Celcius, turning on key to initiate " wait to start cycle " and what I got was a very loud repeated clicking apparently coming from the relays that power the grid heaters.

So I thinks to myself " time to change the relays before it starts to get cold here" .. presently working in an area that will go to minus 32 or 35 , possibly even minus 40.

Changed out the relays and the problem seemed to be resloved ( but it has only been minus 10/12 lately) but two days ago, again at minus 22 , problem has re occured.

So before it gets cold here, what else do I look at??

Appears to be temperature related, and is almost certainly the relays I can hear...provided I can get the heaters working, she starts and runs fine in all other respects.

 

The general cause for relates to chatter is low voltage. If your battery is good then it is most likely in the wiring someplace. Mike

 

Usually a bad PCM. Sorry.

 

Yup, been there, done that, twice.

The relay that's chattering is not the grid relays, its a different one in the same area.

 

JD any chance you could identify the offending relay for me ???