The definitive B4 glow plug relay picture thread

[PaulB]

I've seen all manner of confusion about glow plug relays on the forum, so I'm starting a thread with pictures I hope to clear up some of it. I am posting pictures for a 97 Passat; I hope someone with a 96 Passat takes pictures and posts them here too.

First, please be aware that the Bentley manual does not tell you where these things are. Also there are TWO sections of wiring diagrams, one for the 96 Passat and one for the 97; please make sure you are in the right section when looking at this stuff. For the 97 Passat, see page 118 AKA "No 36/6".

OK, this first picture is an under-dash one; to orient yourself, at the bottom left of the picture is the handle to release the hood. The fuse/relay block has been lifted from its bracket (very easy) and is hanging down, on the right (there is no way to get to the 180 relay without lifting out the fuse/relay block). The knee crash-pad (or whatever that thing is called) has been removed. BTW it is very easy to take off; there are two screws by the door (under a small plastic cover) and one about where your right knee would be (also under a small cover). You then pull the pad out toward the left; this takes a bit of muscle because it is tightly fitted (or maybe there is some glue) connecting it to the passenger-side knee crash pad. Anyway, you can see the relay 180, way up under the dash, against the firewall, and to the left adjacent to the fender.

You should not need to remove the knee pad merely to replace the relay, but any work on its mounting block will require removal of the kneepad. The relay block does come off merely by pulling straight back. However in doing that I stressed the plastic clip on the block so my block won't stay up there any more, oh well!

The next picture shows the fuse/relay block hanging down. The clips rotate on the bracket and then the block just lifts out of the bracket, a very slick design.

In this picture I am holding up the bracket with my thumb on the jumper box. Some have said there is no designation on it but mine has some numbers taped on. In the correct part of the Bentley wiring diagrams you just see a wire which is this jumper. It is the main power coming through for the glow plugs, eventually going up to relay 180. In the 96, the glow plug relay is here, not up against the firewall like it shows a couple photos back.

In this photo I have pulled the glow plug relay 180 off the firewall. The clip on top of the block is now broken. You can feel this click when the relay operates. You have to take it off like this to do any wiring work, like I want to do to have manually-controlled glow plugs.

In the following picture, the tip of my finger is touching the coolant temp sensor plug. If you pull that off (not easy, there is little room to operate) the ECU thinks it is very cold and will operate the glow plugs a full 20 seconds. I don't know if a code is thrown, I haven't checked that yet.

This next picture shows the coolant glow plug relay that is for a completely different set of glowplugs that are there to confuse amateur mechanics. The fuse for that relay is on top under the plastic cover.

Here is one I'm not sure of. There is a big (either 50A or 80A) fuse between the glow plug relay 180, and the battery, but I'm not sure where it is. Is this it?

Anyway, I hope the pictures help. Anyone game for doing the 96 Passat? Post your intentions here first so 3 people don't end up doing it!

 

[PaulB]

BTW, I also solved the mystery of the cannon connector (that brings the power from the relay to the glow plug harness). I got annoyed, this thing is a connector damn it, it is supposed to connect and disconnect. That's what I thought.

First thing I did was remove the two small connectors to the left (i.e. toward the front of the car) from it. You need to do that to get enough room.

There is an outer ring and a wider inner ring, and at top of the inner ring is a pointer that overlaps the outer ring. Do not break this off like I did! Well, it doesn't matter much, but the reason it is there is to indicate where the rotation starts and stops. It is the wider inner ring that rotates, you see, not the outer ring; and the pointer says how far it should rotate. It travels over the unknurled part of the outer ring.

Anyway, grasp the inner ring in a firm grip and rotate to the left or counterclockwise (so the pointer would be traveling over the unknurled part of the outer ring). There is a detent at the start that you have to get over. Rotate all the way until the pointer hits the other end of the blank space. Then pull straight out.

That's the same position you want if you put it back together. If the indicator is broken off like mine you just sorta put it there in about the right place. You push it into the other connector, it's a little fiddly lining things up, then you rotate the center ring back to the right and over the detent.

Now the question is, why would you ever take the thing apart? It provides a sealed environment for the contacts as far as I can see. Maybe if you lived near the ocean it might make sense to spray some dielectric grease in there - maybe! Don't blame me if you screw it up.

I can't see why this connector exists. I'm tempted to take all 15 or 20 wires in there and take them out of the connector and directly solder every stinking one. I believe the connector only served the manufacturing process, that's all. Well, I haven't heard any problems with it so maybe best to leave it alone. I wanted to try though because I'm thinking of substituting another glow plug relay.

Besides that pointer that apparently everyone breaks off, this is not a fragile connector. It is not about to crumble in your hands. At least it looks pretty stout to me.

 

[beetle1963]

Been there done that

You could find that is not so easy. If you do take the wires apart to do away with the 24 pin connector make sure you get the color codes off the wires first because they don't go red to red ,yellow goes to green. just be sure what gose to what before you take them apart. I was loseing power in the connector for the glow plugs and pulled them out to buy pass the connector and broke off other wires and then tried to trace them 2 weeks later I got the car running.

 

[PaulB]

Yet another reason to let that connector alone.

 

[tripl-e]

Relay 180 yet again

Paul B,

I just found this gp thread as the northeast has recently entered the 'instrument panel reset' season for 2007/2008 and I think my reset event is keyed to the gp circuit.

Your picture essay was very helpful and demonstrated the variability between individual cars. My 97's 180 relay is directly above the clutch pedal clipped to the lip formed by the base of the windshield frame and the top edge of the firewall. Completely different from yours. The cylinder gp fuse is adjacent to the relay in is own individual holder.

The large strip fuse in the engine bay in your last picture is, I believe, the cooling fan fuse mounted on the fan controller.

Thanks for your effort with the photos.

Trip Lee
'97 A3B4

 

[BKmetz]

Here is one I'm not sure of.

As tripl-e posted, this is the coolant fan relay and controller. It's separate from the ignition switch and fuse/relay panel because the fan can start and cool down the engine while the engine is off. VW put the fan relay in the engine compartment because they added this feature long after the A3/B4s were designed and didn't have room at the fuse/relay panel. AFAIK, the newer VWs have this as part of the fuse/relay panel.

.

 

[Lug_Nut]

This next picture shows the coolant glow plug relay that is for a completely different set of glowplugs that are there to confuse amateur mechanics. The fuse for that relay is on top under the plastic cover.

There is a big (either 50A or 80A) fuse between the glow plug relay 180, and the battery, but I'm not sure where it is.

The glow plug fuse is visible (barely) in the top of the three images I've left attached. The fuse is to the right of the relay 180 and directly beneath the black foam wire protector. See the single brown wire? Follow it down until it just crosses the two red wires. The top edge of the glow plug fuse is the white item right there.
The 96 Passat has the glow plug relay in the position 16 (thumb in image 2), the 97 where your other images show, and the 98 Jetta where the 97 Passat is, BUT NO JUMPER CUBE!!!. A mechanic attempting to 'repair' my A3 (so the prior owner could sell a running car) installed a glow plug relay in the designed-to-be-empty position 16 and caused the starter motor to spin when the engine was running and the clutch pedal was pressed.
Oh, and that fuse on the left fender is indeed for the cooling fan, Amateur, sheesh!

 

[compu_85]

The A4 cars also have the fan controller in the engine bay as well. It is located under the battery.

The electrical system in your Passat is called Central Electricts II. It was introduced in 1988 in the German production Jettas, and the B3 Passat (which we got here in what, 1990?). The AC system in these cars was much simpler and didn't have any kind of fan controller, just some thermoswitches and relays. (This is what my 1991 Jetta has).

Here is the fuse pannel in my 1991 ECOdiesel. Interesting that some of the posistions have moved around, like the door chime for example.

Few less relays in mine... no power windows or computers to turn on! FWIW the glow plug relay is in the bottom right, number 60.

-Jason

 

[97B4TDi]

How can I "make" a new jumper?

 

[Mcgink]

How can I "make" a new jumper?

I made mine by wire tying and soldering the contacts together inside the relay. In my case (97 B4V) I had a relay plugged in where the jumper belonged. I searched high and low for the correct terminal plugs to just make a jumper wire but had no luck going that route. I also cut off the terminals on the relay that are now useless so that it will never try to function as a relay if someone else changes it out in the future.

 

[97B4TDi]

What terminals are you referring to cutting off? Pictures?

 

[Mcgink]

What terminals are you referring to cutting off? Pictures?

This is in post 98 of thy Glow plug sticky
This is what they look like opened up: I cut the 2 smaller terminals and made it look just like the bridge which is the part on the right.

 

[97B4TDi]

Gotcha! I'll try that, thanks.

If that fails looks like itll be time to attempt finding relay 180

 

[97B4TDi]

This is in post 98 of thy Glow plug sticky
This is what they look like opened up: I cut the 2 smaller terminals and made it look just like the bridge which is the part on the right.

I pulled this and it already was missing two terminals. Should this go back in, in a certain position; refering to the terminals. Guess its onto replacing relay 180... hope that is the final issue.

 

[97B4TDi]

Should this go back in, in a certain position?

"This" refering to the "jumper."

 

[97B4TDi]

I replaced relay 180 and it did nothing to solve my problem. =[

 

[TonyJetta]

What about the fuse?

Tony

 

[97B4TDi]

I just checked that as well as the voltage at the glow plug harness
I am getting 12v at each plug. LOST

What would blow the linkable fuse in the coolant glow plug relay consistently?

 

[Lug_Nut]

97B4, what is the issue you are having?

The coolant plugs have no bearing on the engine starting in the cold. They do help in warming up the driver a bit faster when they work, but they are a completely separate circuit from the engine glow plugs, relay 103, 180, and jumper circuit.
If the coolant glow plug fusible link is continually melting apart that indicates that the resistance is too low and the current is greater than the wires can handle without melting. Replacing a fuse is much easier than replacing wires. There is a dead short, or nearly dead short, somewhere in the black wires coming from the bottom of that coolant relay, or in one or more of the glow plugs to which those wires are connected.

Simply cutting off the two smaller (coil power and ground) legs on the 103 relay will leave the two larger (line and load) legs always open and never passing electrical power through to the glow plugs.
Connecting a ohm meter to the two legs on the cube to the right will show continuity. Electricity can pass from the meter down one lead, through the braided conductor, into the other leg, up the other meter lead, and show a continuous circuit.
Connecting the meter to the modified relay 103 will not conduce power unless the solenoid is electrically magnetized (electricity through the two smaller legs) to close the contact switch between the large legs.
Opening the 103 relay and wedging something in to physically hold that contact switch closed, or as mentioned in post #10 "...soldering the contacts together..." WILL result in a cube acting just like the one on the right, but cutting the small legs alone will be in effect no different than leaving the relay completely out of the socket position 12.

If you do have 12 volts at the harness to the four engine glow plugs then the electrical circuit up to that point is OK.
Are the glow plugs still functional?
I have no lights in my room, but the fuse and wiring check out. I have unscrewed the bulb and have power in the socket. Is it time I should check if maybe the bulb has failed?

 

[97B4TDi]

The problem i am having is rough starts when cold and when I begin driving it feels like it is missing.

I have overlooked the glow plugs cause I just replaced them 2-3 months ago.

 

[TonyJetta]

What about the GP harness? Has this been replaced recently? I'm thinking there may be 1 or 2 contacts that aren't making efficient contact.

Tony

 

[Wiggins Welding]

Hey all, I have a 96 Passat tdi, before I begin, the car started and ran fine before all this. I replaced the 103 glow plugs relay hoping it easy my glowplugs don't come on. I ordered one from an online store that said it was formy car. I put it in today and something made a faint pop sound and now the car just turns over but won't start. I pulled the new relay and noticed after the fact it's a different relay!!! I just assumed it was the right one. The new one is a Bosch 0 281 003 013 with 7 pins and the old one has the big 103 on the front and number 357 911 253 with 4 pins. I put the old one back in and it's still just cranks over. Someone told me to check the fuel shutoff valve on the injection pump with a test light and keys in the on position, no power. I made a jumper cable from the fuel shutoff valve to the battery and could hear it click open, tried starting it but no luck. Any ideas? Did I fry something?? Man I hope not, I haven't even got to run this car anywhere yet, sitting on jackstands waiting for suspension parts lol.

 

[Steve Addy]

The replacement relay you used, (0 281 003 013 Bosch) is equal to the 180 relay that is located elsewhere in the system.

I've not looked at the 103 relay function but I think it's basically just a shunt sending power to the 180 glow controller.

You have to figure out where the 'new' relay sent power to, that has obviously blown something or damaged something in a way that prevents it now from starting.

Steve