A3 / B4 glow plug relay and fuse location

[50harleyrider]

fuse replacement

It sounds like dieseljunkie has the right idea with relocation. If I do elect just to replace it,what fuse at the local NAPA parts store should I use or should I go to the dealer and get a factory replacement?

 

[Lug_Nut]

Relocation is acceptable provided you make absolutely certain of the connections and junctions on the wiring extension, just a 1 ohm resistance increase will make for a significant loss of power at the glow plugs and a localized hot-spot at that less than absolutely perfect junction.

I think fuse relocation is overkill, but then I haven't had any of these buried glow plug fuses open up on my cars.

 

[sfierz]

80 amp maxi fuse works fine available from most car stereo dealers. That's what I replaced mine with. No need to relocated fuse holder.

It sounds like dieseljunkie has the right idea with relocation. If I do elect just to replace it,what fuse at the local NAPA parts store should I use or should I go to the dealer and get a factory replacement?

 

[codeman43311]

i have a steering column guage im going to install on my jetta here pretty soon, now is there anyway i can put a light in it for my glowplug light in it for when other people drive it since the guage will cover the factory light? if so what do i need to tap into?

 

[Mcgink]

My 97 B4V seems to have both relays The one numbered 103 is in position #12 and the one numbered 180 is remotely located above the fuse/relay panel in the "ratsnest" of wires. My 80 AMp fuse under the dash against the firewall checks out and is visibly good as well. I replaced the 50 Amp failed fuse in the block under the hood against the firewall. My GP's and harness are new but I still have a Cel and cold start problems. I can hear a relay noise when I cycle it with Vag-Com but not sure which one is clicking.
I think I'm going to try to swap the the parts from position #12 between the sedan and wagon and see if the problem follows. The sedan fires right up after the glow indicator goes off.

 

[Lug_Nut]

According to the Bentley manual the change over took place at the end of October 1996 for the last of the early, BK/GQ/103 wiring harness, with a November 1996 start for the later, FA/180 wiring harness. Very early 1997 models, those built in June through October of 1996, might therefore have a harness similar to the 1996 models and would require the "103" relay.

McGink, what is the build date of yours? Is it a 103 or a 104? Some have had enclosed jumpers that look like a relay but open them up and they look like the #10 position fog lamp jumper, nothing to click, no contact, just a flat, bent copper conductor between two sockets.

codeman, there are some possible alternative locations where a glow plug lamp can be obtained. The easier is to connect a 12 volt lamp to the relay output, in effect adding a fifth glowing filament to the four already in the engine. The first post has some locations where a lamp can be attached to function as such.

 

[Mcgink]

McGink, what is the build date of yours? Is it a 103 or a 104?

My B4V's build date is 10/96 and the ECU is an FA. I took the 103 relay out and apart this AM and it looks like it's never been actuated. The contacts look brand new. The 180 relay does click when I test the outputs via Vag-Com but with a 103 relay in what's supposed to be a jumper in relay position #12 there would be no output from the 180 relay. Sooo, I can either wire-tie the contacts in the relay together or make a jumper or use the fog light jumper to make it work ( I hope ). With the jumper route, I could donate the brand new 103 relay to cousin Krappy

Some have had enclosed jumpers that look like a relay but open them up and they look like the #10 position fog lamp jumper, nothing to click, no contact, just a flat, bent copper conductor between two sockets.

My Sedan has what I think is one of those. Same size and color as the 103 but no number on it.

 

[Mcgink]

It's fixed, I took the part from relay position #12 from my B4 sedan and compared it to the 103 relay which was in my B4V.

This is what they look like opened up:

I'm thinking that at some point that the PO had a cold start issue and a Tech replaced the wrong part. The part on the right is callled a "Bridge" and the part # is: 3A0 941 817. FYI the part is obsolete according to the local VW dealer's parts dept.
Without the info/pics in the begining of this thread, I would no doubt be still scratching my head trying to diagnose the root cause of my cold start issue.
Thank you

 

[codeman43311]

alright thanks lug nut, i was thinking about doing that but i would really hate to mess somthing up

 

[sfierz]

Wow, nice catch. Would never think to look at that.

It's fixed, I took the part from relay position #12 from my B4 sedan and compared it to the 103 relay which was in my B4V.

This is what they look like opened up:

I'm thinking that at some point that the PO had a cold start issue and a Tech replaced the wrong part. The part on the right is callled a "Bridge" and the part # is: 3A0 941 817. FYI the part is obsolete according to the local VW dealer's parts dept.
Without the info/pics in the begining of this thread, I would no doubt be still scratching my head trying to diagnose the root cause of my cold start issue.
Thank you

 

[kybishop]

I have a 98 A3 jetta. Had no troubles at all starting it last winter. This winters first cold spell it had trouble. I put four new Bosch glow plugs in and it may be a bit better but not much. It wont start with temps in the mid 20's. Sputters a while then dies with some white smoke. It will start sometimes in the mid to high 20's but after a second or two of some rough idling or sputtering.

Paramedic set the timing year before last and I put a new fuel filter on then too and it ran great all last winter. Until now, this winter. I probably need to change the filter again.

Fellow forum member Paramedic advised me to check my glow plug fuse or relay. Looking at my fuse and relay block confused me a bit. It is different than the picture of the 98 A3 on this thread.

The main block of 12 relay sockets are the same. The differences are the added ones above. Where the photo shows three sockets added above with a 53 in the far right socket and an empty one to the left of it. Then next to the left is the glow plug 180 with the 50 amp fuse above it. Mine just has 2 socket for relays here. The one on the far right has a 173 in it and the next to the left has a 53 in it with the 50 amp glow plug fuse above it. Then it has three smaller fuses to the left.

I was thinking I need to take the 53 out and put the proper 180 in below the 50 amp glow plug fuse?

Thanks for any help.

Kevin

 

[Lug_Nut]

NO! WAIT!
The 53 is a generic (single pole, single throw, four pin, relay used for things like the horn or fog lamps. If that is the proper relay then putting in a glow plug relay will cause damage. Unfortunately the only way to tell is to look at the size and color of the wires that go to and from the back of this relay's mounting block.
The glow plug relay mount will have big 6 mm cross section (about 10 gauge) red jacketed wires. Almost nothing else draws as much power or needs such fat wires.
The 173 is the relay for the Day Running Lights.

 

[kybishop]

Okay.

Thanks for the reply. I did not pull anything yet. I don't have a 180 anywhere on my relay block but the PO gave me a new relay in a box. I looked and it is the 180.

Not sure if it would be related but my TDI has always had quite an appetite for glow plugs. Goes through them fairly quickly I think. Need to track it but seems like I am always having one fail.

The glowplug light comes on and stays on for several seconds when it's cold.

Oh yeah, I have two number 53 relays in my relay block. The one below the glow plug fuse and the other down in the main block of 12.

I will look on the back for the heavy gauge wiring. I will also look to replace the 50 amp fuse. Does it just pull out like regular blade fuses?

Again, appreciate your quick response.

Kevin

 

[Lug_Nut]

The indicator in the instrument cluster is separate from the relay, fuse, and plugs. It would still come on if all the other stuff were removed. Don't use the dash indicator as a sign that the glow plug system is working.
The 50 amp fuse pulls out.

 

[kybishop]

Next.

Glow plug fuse looked okay but replaced with a new one. Replaced the fuel filter and replaced the air filter while I had it open. No luck.

Tried to locate the glow plug relay. I tried to find the socket with the large wires but the fuse/relay block is so close to the firewall and so many wires I could not see where they were going. Too tight.

It started fine all last winter. Not sure which of these should be the glow plug relay on my fuse block.

Drawing of my relay/fuse block and the numbers. Shaded spots are blank sockets. 50A glow plug fuse above the 53 relay at the top.

http://www.flickr.com/photos/31259971@N04/5272889344/

Thanks.

 

[sfierz]

Did you check the metal strip fuses in the engine compartment? Somebody correct me if I am wrong but I believe there is at least one or two in there that might affect glow plug operation.

Glow plug fuse looked okay but replaced with a new one. Replaced the fuel filter and replaced the air filter while I had it open. No luck.

Tried to locate the glow plug relay. I tried to find the socket with the large wires but the fuse/relay block is so close to the firewall and so many wires I could not see where they were going. Too tight.

It started fine all last winter. Not sure which of these should be the glow plug relay on my fuse block.

Drawing of my relay/fuse block and the numbers. Shaded spots are blank sockets. 50A glow plug fuse above the 53 relay at the top.

http://www.flickr.com/photos/31259971@N04/5272889344/

Thanks.

 

[TonyJetta]

Did you check the metal strip fuses in the engine compartment? Somebody correct me if I am wrong but I believe there is at least one or two in there that might affect glow plug operation.

I believe you are referring to the coolant glow plug controller. That's NOT the glow plugs used for starting.

Tony

 

[TonyJetta]

kybishop,
Lets go back to the basics.
1) You have new glow plug in the head, correct?
2) Have you checked for 12V at each of the 4 GP contact on the harness?
TO do this:
A) Disconnect the Coolant Temp Sensor; that will let the GP relay stay on for it's max time.
B) Turn the key to ON.
C) Check for 12V at each of the GP contacts.
D) If you Don't have 12V at each of the 4 contacts, you may have a bad relay.
E) If you have <12V (battery voltage) at each contact, the fuse, relay, or it's associated wiring may be on it's way out.
F) If you have 12V at only 2 of the GP contacts, look over your GP harness, where it plugs into the engine harness. I'll bet only one wire is soldered or plugged in. Fix, as necessary.

Post back any questions or findings.

Tony

 

[sfierz]

Thanks, Tony. I might have been thinking of our A4 New Beetle. It does have some strip fuses that control the engine glow plugs.

I believe you are referring to the coolant glow plug controller. That's NOT the glow plugs used for starting.

Tony

 

[kybishop]

Correct, I do have new glow plugs in the head.

I will check the harness and voltage as you mention.

I am not sure where to disconnect the coolant sensor but will look to do this.

Thanks and I will report back.

Kevin

 

[TonyJetta]

I am not sure where to disconnect the coolant sensor but will look to do this.

Tony

 

[kybishop]

Quick question Tony.

Your D: on the list above.

"D) If you have 12V at each of the 4 contacts, you may have a bad relay."

Shouldn't I have 12V at each? D confused me as if I have 12V at all 4 the relay may me bad?

Thanks.

 

[TonyJetta]

Quick question Tony.

Your D: on the list above.

"D) If you DON'T have 12V at each of the 4 contacts, you may have a bad relay."

Shouldn't I have 12V at each? D confused me as if I have 12V at all 4 the relay may me bad?

Thanks.

Corrected! Thanks for asking, before buying parts or troubleshooting. Hope I didn't mislead anyone.

Tony

 

[kybishop]

Been cold here. Update. Glow plug harness tested good voltage at all four.

I am now thinking fuel pump. I fill the fuel filter, re-connect. Car sits a bit and I go to start. Will go to idle a second then gets rougher then dies. Try again and won't start. Look at fuel filter and there is no fuel at top of filter. Hoses and connections look good. I have filled it three times and it keeps emptying it.

I think it was a glow plug problem with no start when it got cold. Now fuel pump relay or pump itself.

 

[rdkern]

No fuel in filter means a leak, not a bad fuel pump. Perhaps gelled fuel in the line from the tank? Bad pickup back there?

 

[sfierz]

Yeah, a bad pump wouldn't be running the fuel out of the filter. I agree, frozen line, bad pickup in the tank, fuel line leak somewhere before the filter?

 

[rdkern]

Yeah, a bad pump wouldn't be running the fuel out of the filter. I agree, frozen line, bad pickup in the tank, fuel line leak somewhere before the filter?

Yep. If it's not "gelling" cold, most likely either bad pickup or air leak at the filter (the "T"). Look at the filter possibility first. Put some petroleum jelly around that connection (on the outside, not on the "o" ring. Don't want that stuff in your fuel, I would guess). This will sometimes seal the leak temporarily and let you know what to fix.

 

[kybishop]

Still no start. Figured this was getting away from the glow plug/relay sticky so;

http://forums.tdiclub.com/showthread.php?p=3234835#post3234835

 

[idleofwight]

How long do glow plugs last? How do u know when they are bad?

Here is my deal.

I get a light, stays on 20 sec. everytime.
Fuse is there inside
the one outside is constantly blowing, so I replaced it with something else and now that is fried, but I figured since it is a coolant heater not that big of a deal.

could the fuse be bad and the light still comes on?

 

[Lug_Nut]

The light is driven by the ECU. One hopes that the glow plugs are also on through their separate fused circuit, but there is no reason to presume that the cluster illumination is a certain indication of electrical power to any of the glow plugs.

The temperature sender is two units in one housing. One sender drives the gauge in the cluster, the other, the ECU. The ECU half may have failed, but can't be replaced separately.
A constant 20 second duration, regardless of air temperature or engine temperature, indicates that the ECU doesn't know the temperature and defaults to maximum cold values.
Check with VCDS, and check the wiring back to the ECU, too. Twenty seconds indicates an open circuit (bad connection, bad sender, bad wiring).