gpr power issues

[trooper632]

put a new ST-85 gpr on the cucv, and still wont activate glow plug, tested plugs and they seem to be working. cucv has the manual gpr switch and has had it for several years. Got power to the gpr but no output power on any of the three lugs on it. When button is pushed it still doesnt have any power to the three lugs, replaced button with new one still nothing, checked and tightend ground, checked fusable links by fuel filter, Im lost, both batterys are fully charged truck cranks over fine. the wait light doesnt even come on anymore now, need help.

 

[Warthog]

Here is a easy test:

red wire to the top lug of the relay
orange wires on the bottom lug going to the GPs
disconnect the two small wires on the coil portion
supply 12v to one of the small terminals
connect to ground on the other small lug

You should here the relay engage and make a click/clunking sound

All the relay is doing is using 12v to energize the internal coil, which pulls the internal disk which closes the circuit for the mail power to flow

On a stock system the small pink/black wire has 12v at all times. The manual switch or the controller card should be suppling the "ground" to close the circuit and energize the relay. The light blue wire is the gound.

We don't how you manual switch is wired. The attached diagram shows the easiest way to do it.

 

[trooper632]

removed blue wire off of gpr, and connected one wire from the push button to the post where the blue wire was, connected a ground wire to the other terminal of the switch.

 

[trooper632]

turnes out the glow plug card had a burnt spot on it, Removed it and truck started right up.

 

[tgtaylor64]

Does the pink/black wire have 12 VDC at all times or just when the key is turned?

 

[corelokt]

Pink and black, w/ the switch. There is a small black plug under the column. It grounds the wait light and has power from the switch.