My glow plugs have stopped working the light on the dash comes on and goes out but the glow plugs dont work unless you run a wire from the battery straight to them, any help would be great :-) dose or can anybody tell me where the heater glow plug control unit is on a pejero 1991 2.5 turbo diesel and expain what it looks like i would be so great full for anyone to help me thank you......

Hi. I'm not sure at this point. Your information sounds like a power or charging issue. How is the battery, charging system and related wiring, cables, terminals and grounds? There also could be a fault related to the ECU. A poor connection, shorted wire or damaged component. The glow plug light shouldn't be coming on while you are driving. You mentioned that power returns if the brake light goes out. Which brake light (Dash or Tail lamps)? Are you also saying that power returns if you release the fuel pedal? Does the vehicle lose power while under a load? The more information the better. You are there and are the eyes and ears. Please let me know else I can do to help. Good Luck.

replace the light illuminator on dash test light to see if your getting an electrical connection thats simple and its dyi

Its possible the glow plugs when its warm the diesel is warm and starts more easily when its cold the diesle needs warming more so the glow plugs work harder in the winter only way i know how to test them is to take 1 out at a time turn the pre ignition on so the glow plug light comes on and the plug should glow red if not buy the 4 and replace the lot you could also check the wireing going to the plugs hope this helps ivan

HAVE YOU CHECKED WHETHER THE FAULT IS ON THE GLOW PLUGS RELAY?

the glow plugs work through a relay so check the relay and wiring for the relay from the ignition switch

If you can't pull the codes from the pcm it has either died or lost it's ground assuming it has power. I would try to get a wiring diagram and check both the power and the ground for the computer itself, because it is what turns on the pump and the wait to start light.

i condem all the sensor and circuit of the module of the glow plug as well as rha relay

glow plug relay in the engine bay fuse box, check this they wear out over time.

When you turn on the key, a relay engages for a few seconds and heats up the glow plugs. It sounds like the relay is not passing current, which could indicate either corroded contacts, or a bad relay all together. I would guess the former since your panel light indicates the relay is functioning correctly. I would suggest replacing the relay, or possibly if you feel comfortable with it, disassemble the relay and clean the contacts.