When I started my 2002 f350 to drive I noticed the glow plug light icon on the left side of the instrument custer would not turn off. When I arrived at the store ,turned off the motor and restarted it , it cycled normally and turned off. I need to drive tonight 200 miles to get home, is this light on the dash going to be a problem??? thanks guys

 

Invest in a $10 test light at an auto parts store. Start the engine, let it run for about a minute and check the output side of the glow plug relay (one brown and one yellow wire). If it's not powered up, you're good to go....WTS light on or not.

I posted two tables here recently in a thread that showed the relationship between what the glow plug relay is doing vs. what the wait to start light is programmed to do. There is NO relationship between the two as they are independently controlled by the PCM.

You are not going to want to drive the truck 200 miles with the glow plugs on. You can always disconnect one of the two control side wires from the relay.....that way the GPs will not be able to turn on.

 

Here's the post.

https://www.ford-trucks.com/forums/8...ml#post7700314

 

thank you I'm going to read this infor and check the truck out

 

One thing you can do is invest in a small LED. Mount the LED in your dash and run a wire to the side of the GPR that is not always hot. You can ground it on the threaded post you use to secure the GPR. Then the light will go on any time the GPR is on. No WTS light worries.

It's basically the same as having a test light on there 24/7. I've got mine mounted in my A pillar gauge pod.

 

I have a voltmeter on the yellow\brown on the GPR and the ground? on the neg side of the battery. But no readings. What do I put the leads on to test?

 

Sorry, I don't do colors. On the GPR there are 2 large posts. One of them is the 12 volt power coming in from the battery. It is hot all the time. Check both large posts against a good ground. The other large post is what will send the power to the glow plugs when the key is turned on. It should read 0 volts with the key off, and about 1 volt less than the other large post when the key is first turned on, but will go back to 0 after several seconds. If the light on the dash stays on, but the 2nd big post on the GPR reads 0 volts, your glow plugs are safe and it's an electrical issue.

If you decide to unhook a wire from the GPR, try not to unhook the battery feed wires (has a rubber boot on it). That way it doesn't accidentally short to ground and cause more problems.

 

Thanks! I have power to the large post which is hot always. The other large post shows no voltage when the key is turned on or otherwise. Starts fine. Glow plug icon shuts off as designed. Freak happening on light staying on?

 

probably, sometimes things go weird for a minute. and i have checked and checked and everything is fine.