Glow plug relay problem

[Eric Selinger]

Well I finally got my rebuilt engine installed and it runs good! However, I have no glow plug light or power to the glow plugs. I can use a jumper wire across the two posts and it will heat em and the truck will start perfect(I also get a glow plug light on inside when I jump the two posts on the relay).How do I tell if the relay is bad(it worked well when I took it out of the truck)? How does one wire in a manual glow plug switch?
Is there a way to test the relay before I replace it? Are there any aftermarket relays that are better or cost less?

Any help would be appreciated. I am so ready after 9 months to drive this thing.

Thanks to all for the information and to "more power" for thinking ahead..


Thanks!

Eric Selinger
1994 CC TD hypertech chip, 4" exhaust, & an amsoil air filter.

[Hubert]

I think I have a similar problem and was reading other posts.

Read you might want to check coolant temp sensor. Read thats what tells the computer to turn on the glow plugs.

What voltage do you measure at the glow plug connection. I measured just over 9v on the No. 1 cylinder while the wait to start light was on.

[charliepeterson]

Hubert's right, try unplugging the coolant temperature switch and start the truck.

[joed]

Follow-up similar question:

When the glow plug relays fail, do they usually store a trouble code (I notice codes are listed for glow voltage high/low,at least on OBD-II trucks)?

The reason I ask it is seems like my glow times are shorter than they used to be and am noticing a little more white smoke on cold startups. I replaced the coolant temp sensor (last year I think), put in Kennedy's quick heats last year, and have fresh batteries. Could the relay be working, but just not as well?

Thanks in advance. Joe.