Thought I would pass on what it looks like when the GPR goes bad. I had a hard time starting the truck during the past couple of weeks (never got above 30 deg here in MD). I read NCHornet's write up on the GPR and swapped out the stock for the Stancor HD relay. I can tell what the problem was when I pulled out the old relay.
You can see the pitting on the contacts. The stock relay was never up to the high amperage the glow plug circuit demands. While I was waiting for the Stancor to arrive, I was using a screw driver to short the terminals to run the glow plugs, the screw driver got HOT! You can tell by the pics the same thing was happening on the relay.
Came out in pieces. If you have a failing relay, don't put back in the stock relay, get the Stancor HD upgrade. Well worth it!
You can see the pitting on the contacts. The stock relay was never up to the high amperage the glow plug circuit demands. While I was waiting for the Stancor to arrive, I was using a screw driver to short the terminals to run the glow plugs, the screw driver got HOT! You can tell by the pics the same thing was happening on the relay.
Came out in pieces. If you have a failing relay, don't put back in the stock relay, get the Stancor HD upgrade. Well worth it!