Something just started happening today. It sounds like a relay turning on and off. The sound can be heard under the dash but over the steering column and under the hood on the driver side firewall. The relay sound happens with the truck is running and not running. I can feel the clicking on a unit that I believe is the window wiper motor in the engine compartment on the firewall. I unplugged it and the clicking noise would continue. So I am counting that one out. Although I could still feel the clicking threw this unit. It is not a constant click on and click off, on off, on off... it happens about every 30 seconds or so. When I was driving tonight I noticed that when it clicks on the lights would dim a little and when it would click off the lights would brighten back up. The lights dim the same way the glow plugs make them dim when the wait to start light goes on and off right after it is started. It seems like it maybe the glow plug relay but the wait to start light does not turn on and off with the relay clicking noise.. I have no idea where the glow plug relay is though.

Anyone experience something similiar and resolve there problem and or any suggestions.

Thanks Friends

What was the air temp? what temp was your truck running at? Had you run the truck long enough to get the truck up to running temp? My vehicles all do this til they get to temp when cold. I believe it might be the fuel preheater.

What was the air temp? what temp was your truck running at? Had you run the truck long enough to get the truck up to running temp? My vehicles all do this til they get to temp when cold. I believe it might be the fuel preheater.

I have had the truck for almost a year. I live in central CA and the temps have been fairly warm still, mid 70's low 80's. I thing its the glow plug realy cycling on and off but not sure. thanks..

I still would like to know where the glow plug relays are?

coolant temp sensor? can you plug in to a scanner and get a reading?

This might be a good reason to purchase a scan tool. :) I added pictures to another link (http://dieselplace.com/forum/showthread.php?p=1365697&posted=1#post1365697) in the electrical forum here at the Diesel Place.



Thanks

as for the pics you posted, I don't know what they are. The glow plug relay is mounted to the right of the fuel filter (as you're standing in front of your truck). You can trace one of the glow plug wires from a driver's side gp back to it. There also should be a brown grounding wire (10ga) that connects to the block at the tranny dip stick tube head stud. a bad ground can cause weird things to happen. (I don't know if it could cause your glow plugs to come on randomly)

Whenever there's an electrical gremlin, it's a good idea to clean and inspect all battery and ground connections. If all connections are good, then it's ok to start spending money on parts.....

is there anyone near you with a scanner?