Trk has always started and ran fine, a few weeks ago it failed to start b/c glow plug relay was not kicking, i jump across both post on glow plug comtroller and it fired right up.
i replaced the glow plug relay with testing wiring first and to my suprize it still didnt work,
all the books show a fuse under hood for glow plugs but on mine fuse is mia.. There is no wire connectors in box where it shows fuse goes... my ? is, is there a fuse or something im over looking for this or does ecm control all of it when ignition is turned on ?
i checked for power to relay while my wifey turned key on and there is no power coming from switch.. Thanks in advance for any help!!!

 

Check the relay, might not be working. I had issues with mine last week cause of dirty contacts.

 

Here you go,wiring diagram:

 

Hey guys, my issue is a little different. Glow plugs were working before I replaced the IP. Now they do not work at all. No indicator light, no relay clicking, nothing. There is power to the 12V supply lug on the relay but nothing coming out of the relay. I checked the wires going into the relay and I do not appear to have any power telling the relay to work. Any ideas? Where does the relay get its control power?

 

The ECM controls glow function.

Make sure that the relay base is grounded securely.

 

Hi I have the same problem the glow plug light does not come on and the truck won't start it cranks but wont start I have installed a manual glow plug switch but still won't start did you find out what was the problem?

 

You need to check for power at each glow plug terminal when they are supposed to activate-possible that the ECT or coolant temp switch is faulty that is loacted in the coolant crossover? ,AC Delco ONLY for replacement!

Check the glow plugs as well by removing them and powering each up with a battery-carefull they get very hot.

The glows should glow their entire length in 8-10 seconds,if only the first 1/4 glows in that time they are past their prime and need replaced with Bosch duratherms.