Author Topic: Weird glow plug light problem (Read 4469 times)

silvertdi · « **on:** January 31, 2008, 08:15:34 pm »

Your help is needed and appreciated.

When an electrical load is placed on the car (brake lights come on, turn signals, wipers, etc.) the glow plug light flashes for a split second. What could this be? alternator connections are tight.

Thanks.

Quantum TD · « **Reply #1 on:** January 31, 2008, 09:11:22 pm »

First: is the belt tight?

If so, the it sounds like either your voltage regulator or alternator are bad. Sometimes you can just replace the voltage regulator and solve the problem. But a new voltage regulator will usually only fix the problem for about 30k.

In the end, you may need to replace the alt.

BlackTieTD · « **Reply #2 on:** February 01, 2008, 07:43:41 am »

i had this problem come up recently as well after i changed the alternator belt and it settled into use and got a little slack. although i haven't been bothered to tighten the belt yet, i'm fairly certain thats what it is in my case. check the belt. apparently VW spec is 2mm of deflection when pushed down in the middle of the top surface which seems very tight to me.

silvertdi · « **Reply #3 on:** February 01, 2008, 07:58:29 pm »

My belt seems very tight. Its a Gates and is probably a smidge longer than the OEM because I'm maxed out on my alternator adjustment. It does have more than 2mm travel...probably like 5 - 7mm.

I was thinking about the voltage regulator. I think if I change that I'd also have to change the diode trio. I think they have to be done as a pair or you'll have alternator failure down the road. I find it weird that the battery light doesn't flash...only the glow plug light.

Quantum TD · « **Reply #4 on:** February 01, 2008, 08:36:17 pm »

Quote from: "silvertdi"

I find it weird that the battery light doesn't flash...only the glow plug light.

Hmm. Does your battery light come on when you turn the key to the accessory position? If not, then your LED for the BATT may be shot. I've heard that if it's bad, it can affect charging.

If the LED is good, AND you have a MK 2 car, then your water separator may be loaded with water. It has a sensor in the separator tank that activates the glow plug light when in need of a draining. I've seen it a few times, especially on high mileage MK 2s. The light will flicker at times.

To drain the separator, just loosen the drain cock, and push it in and out (like a pump). That should do it.

silvertdi · « **Reply #5 on:** February 01, 2008, 09:57:59 pm »

The battery light works. When I first start it up it comes on until the engine is revved a little. Then it goes out.

Its a mk1.