6.5 wts light works but glow plugs don’t
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Verify you have 12v. going to the glow plug relay and with a little help from a friend, have them cycle the key while you verify 12v. going from the relay to the glows.
If you do not see the voltage from the relay to the glows replace the glow plug relay ( Use AC/Delco brand only!)
As OkDually said, check for voltage from the relay. A quick check while troubleshooting can be done with a test light.
Make sure you have voltage to the relay, then have someone turn the key and check the “output” side of the relay. If that doesn’t light up the light, start checking wiring going to it. If the test light lights up on the output side of the relay, start checking one by one for power at the plugs themselves to make sure there is not a break in the wiring from the relay.
Make sure you have voltage to the relay, then have someone turn the key and check the “output” side of the relay. If that doesn’t light up the light, start checking wiring going to it. If the test light lights up on the output side of the relay, start checking one by one for power at the plugs themselves to make sure there is not a break in the wiring from the relay.
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I’ve seen cases where the positive cable going to the glow plug relay was put on the wrong stud.If your facing the engine with the hood open that positive wire should be on the left stud.And the wiring heading to the glow plugs themselves should be on the stud to the right.This is of course is the 94 and up black relay.The older 85-93 white relay is the opposite hookup.That’s what I’ve discovered on a few of these trucks when someone installs a new relay.
Just something I wanted to mention.
Just something I wanted to mention.
It only glows for around 6 seconds at the longest interval so if you don't measure it between that 6 seconds period (very fast), you will not get anything.
I am not sure if there should be resistant in the GP cables.
Hopefully, Glagulator can chime in.
I am not sure if there should be resistant in the GP cables.
Hopefully, Glagulator can chime in.
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Checking all 8 GP's like that will not tell you much.
They need to be disconnected and checked one at a time.
1 to 6 ohms is considered normal for these GP's. They are basically a dead short.
They can also check good and still not work.
The harness wires should have close to zero resistance.
Make sure the "glow plug signal connector" is connected, single wire coming off the 15-pin connector near the GPR.
On your 1998 the PCM turns on the WTS lamp, not actual voltage from the glows.
They need to be disconnected and checked one at a time.
1 to 6 ohms is considered normal for these GP's. They are basically a dead short.
They can also check good and still not work.
The harness wires should have close to zero resistance.
Make sure the "glow plug signal connector" is connected, single wire coming off the 15-pin connector near the GPR.
On your 1998 the PCM turns on the WTS lamp, not actual voltage from the glows.
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