m1008 glow plug/wait light issue

I clipped my test light on it and checked all the fuses for power. I just have it clipped on and the test light lights. I think that means I have ground. I agree that it is strange. I changed the glow plug harness and still have the same symptoms. Now I don't feel bad when I say my new truck has no cable attachment to the parking brake. It is just a push button like my Wife's car. Electric Parking Brake. Sounds good to me. I am going to dive into this Red Devil M1009 as soon as I get home today. I will recheck the ground. But being that everything else works in the cluster I am assuming the ground is good. I have a good Fluke multi meter and barely know how to use it. I use a test light on most jobs. I am NOT very strong on electrical issues. I will figure it out. Or never give up.

Two quick thoughts...

A test light is often better than a meter, except when it's not.

It's possible to have a partial ground, and it may be that you have enough ground to light a light, but not pull in the relay. I'm not sure how much current that relay needs to pull it in. Need to look for that, but for now I have to get back to work....

After long thought and 9 hours on my full time job I was able to come home and solve the problem. I think the initial problem was all the hacking that had been done to this poor Red Devil. I had pulled all the glow plugs tested them and reinstalled them. The relay on the fire wall was incorrect. I found another relay in the truck that looked correct so I installed it. I think it did not have an isolated ground on the relay and that is why the glow plugs would stay engaged. Well guess what? All 8 glow plugs were burnt out as I had feared they would be when I discovered that the relay was staying engaged the whole time the key was on. All but 1 glow plug I was able to get out will shear force and a pry bar. I had to remove the delivery nozzle on the second one back on the drivers side. It snapped off and needed the curved needle nose to get the tip to come out. That and an awl to push the tip back in to the needle nose jaws. Scary business. I pulled the circuit card from my M1028 and installed 8 new A C Delco 13G glow plugs. I hit the key the relay engaged, the light lit and it started right up after the wait light went out. I had the test light ready and it cycled the glow plugs 3 times as it idled and then they quit cycling. All is good at base camp. I knew I could get thru this with a little help and thought. I read and thought and then I pulled the perfect running M1028 up and disconnected the temperature sensor wire and went to work with a test light. In 5 minutes I was onto the glow plug removal and heading down the right path. Thank you Obi-Wan for the power. It was getting dark and I hung it up for the night. Hope to get this Red Devil out of here in the next week.

cucvrus said:

I think it did not have an isolated ground on the relay and that is why the glow plugs would stay engaged.

Click to expand...

Yep. That relay must be an isolated ground relay, or it's frying time again, you're gonna burn GPs. (Apologies to Eddie Arnold.)


Nice work!



https://www.youtube.com/watch?v=VlbhG8tdOvU

Still wondering what that thing is on the injection pump. Does anyone know a good part number for a fast idle solenoid? The GM part number is discontinued.

The picture is too fuzzy for me. Can you get a better one? I'm intrigued.....

I had to dig into my stash and unbox a GM circuit card. I slipped it in the box and turned the key. Clunk the glow plugs solenoid engaged and cycled. I started the M1009 and checked the lower stud on the relay. It cycled 4 times and shut the glow plugs off. Happy Happy. The shift selector attachment leg was broken off the cluster housing. Easy fix. Grease the slide and move the indicator needle back and forth. Easy fix a sheet metal screw with a shoulder on it. We used these on the tether of the gas caps 20 years ago and I stashed some. Great for slave cable tethers and gear selector cable guide. I drilled an 1/8" hole in the steel dash and inserted the cable behind the head of the screw and tightened the screw. I checked the adjustment in all gear positions and called it fixed. I have the cluster back in the Red Devil and called it a day. It continues to rain and make things muddy everywhere. I want to get this job wrapped up and back to the owner. I have a metal brake line on the left rear axle to replace. it is blown out and leaking brake fluid. Happy New Year.