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vwnewton, VW Owner,ASE Master and L1 Advanced
Category: VW
Satisfied Customers: 307
Experience:  25 years of VW obsession turned into a job, last 15 years as a VW Tech.
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I have a 99 new beetle diesel. Can't get glow plugs to work

Customer Question

I have a 99 new beetle diesel. Can't get glow plugs to work like they are supposed to.No power to glow plug harness. When engine is cold, glow plug light stays on for less than 2 sec. Relay is good,installed new glow plugs,maxi fuse is good,newer glow plug harness. Ran a jumper wire to each glow plug, & they work. Head is grounded like it should be. Disconnected coolant sensor and then power goes to glow plug harness for a good 20 sec. Installed new coolant sensor, figuring that was the issue... with new sensor installed, glow plug light still stays on less than2 seconds, & no power to glow plug harness Also air temp was less than 50 deg. Is there by chance a head temp sensor somewhere?
Submitted: 1 year ago.
Category: VW
Expert:  Wolfgang replied 1 year ago.

Thanks for choosing Just Answer . I'm Wolfgang here to help!!

I am confident we can resolve your problem together. Please
understand that I don't know your skill level. In most cases when you have a problem
with the way the vehicle performs, specialized tooling is required to acquire computer
data/information or engine testing results. We didn’t build these complicated vehicles; we
just diagnose and fix them. Also understand that I can't see, smell, hear, or touch the
vehicle either, so it may take a few replies to get to satisfactory results. Note there may be an issue where the complexity of the issue will require a Premium Service. This service will be an addition to the normal question cost. Usually it does not come down to this but keep in mind!! I am also going to direct you with the fastest, easiest and most common things to check first. Please be
patient and permit me to do what I do best.
I also try to give all of the information you may need, expecting a “positive rating” in
return. I will also continue assisting you after you have rated me, if necessary. If there
is any reason I cannot get a positive rating, please let me know why “in advance”, so I
can go another direction for you. I am sorry you’re having this problem; I’ll help you
through it.
Below is my first answer or request for more information. If you do not understand it, or you need more information from me, or need me to go in more detail.

i do need some more info please.

  • is there an issue where the vehicle is not starting?
  • is the check engine light on?
  • if so what codes are stored?
  • what are the measured resistances of each glow plug?


Customer: replied 1 year ago.
I am very mechanically inclined....check engine light is on...glow plug malfunction. don't remember what p # came up. Brand new glow plugs. Starts very rough when below 50 deg.
Customer: replied 1 year ago.
Thinkn of putn them on a push button switch.
Expert:  Wolfgang replied 1 year ago.

do not do that!!!! p0380? got to have the codes!!! what is the resistance of each glow plug?

Customer: replied 1 year ago.
didnt do a resistance test, cuz they are brand new. ran a jumper wire from battery 2 each glow plug. got spark @ each glow plug and wire heated up. might have been the 0380 code, had a friend of mine plug in his snap on scanner. I am not by vehicle right now. Why can't i toggle them?
Expert:  Wolfgang replied 1 year ago.

because with a bypass you can go into a limp mode (reduced power). so your real issue is the starting rough in the morning. first thing is the injection pump timing needs to be checked and a VAG COM scan tool is needed because it is read by the scanner and adjusted if needed by the injection pump. hence the codes may give other faults .

snap on scanner is good if euro is loaded and used . global obd may not get manufacturer specific codes

Customer: replied 1 year ago.
Could you send this info to my email address plz? I am out of town 4 work right now, & will have to get my buddy over with scanner again. I am used to american glow plug systems... solenoid, glow plugs etc... simple.
From what I've read on these, this a common issue?
Expert:  Wolfgang replied 1 year ago.

due to site regulations that is not possible . the only way is to authorize the premium service offer!! Site rules!!

Customer: replied 1 year ago.
is the glow plug issue with vw diesels common?
Expert:  Wolfgang replied 1 year ago.

not too common . i have seen glow plugs get high resistance from time to time. i do believe you have a different issue with startup!!

Customer: replied 1 year ago.
no disrespect... ur not helpn me much. i have addessed every issue pertaining to the system. something goofy.
Expert:  Wolfgang replied 1 year ago.

no disrespect either but without the codes and a scan tool how can i help out in my end . help me to help you!!