A3 / B4 glow plug relay and fuse location

[brit mk2t]

Does anyone know what the 103 relay looks for in terms of glow plug monitoring. I have a 1996 passat, changed out the plugs, harness and relay, checked the 50A fuse, checked for voltage at the harness to each GP... everything checks out and i have no issues starting, but the CEL will not go away, as soon as i reset it using the vagcom it comes right back... i think the code is 01050 glow plug monitoring intermittent .... i will double check later, any help would be greatly appreciated.

 

[compu_85]

It sounds like you have a later ECU installed in your car. The cars with the old 1-output relay do not have glow plug monitoring.

-J

 

[TonyJetta]

brit mk2t,
when you scan the car, what is the full part number for the ECU?

Tony

 

[Lug_Nut]

Specifically the two letters after the number 028 906 021 _ _ ?

 

[brit mk2t]

Yeah you guys are right, man i missed that one... the previous owner must have switched it, which now explains the issue i was having with the CEL on the cluster being intermittant (i think the PO tired to disable it) i had the cluster repaired by Derek at Chubsauto, so the ecu in the car is an FA, if i was to just keep the FA, does anyone know the best way to trick the ecu to think the the glow pulg monitoring is fine, like feedit 12v or whatever the 180 relay feeds the ecu to tell it its fine.
Thanks

It sounds like you have a later ECU installed in your car. The cars with the old 1-output relay do not have glow plug monitoring.

-J

 

[97B4TDi]

I am next to pulling my hair out over my glow plug problem!

I just replaced relay 180, checked the jumper and fuse and all seems well... any help?

 

[TonyJetta]

I am next to pulling my hair out over my glow plug problem!

I just replaced relay 180, checked the jumper and fuse and all seems well... any help?

Dude! You already have a thread going! If you wanted more attention to the thread, post a link to it, in this thread.

Link...

Tony

 

[racerjim]

I agree this thread is great. I looked at my relays on my 96' TDI passat compared to the picture at the beginning of this thread and mine was missing both 72 relays and the 110 relay. The relay in the slot where 103 should be for the glow was some taller one with like (7) spades on it? part number was nella 90987500.

I checked the main fuse up on the firewall above the fuse box and the fuse was good.

With the 103 relay out and the coolant temp wire hooked up the glow light on the dash goes on and off in about 1-2 seconds and with the coolant temp wire disconnected it stays on for about seconds so that all seems right.

With the weird Nella relay installed in the 103 relay slot I do get power to all (4) of the glow plug harness connections but the glow dash light does not go out at all.

I'm assuming I need to go get the correct 103 relay but wanted to know what the 72 and 110 relays do? My car is very hard starting and I want to make sure the glow system is working correctly.

 

[TonyJetta]

Given there are mid-year model differences. Such that the relay layout may not exactly match yours.

I agree this thread is great. I looked at my relays on my 96' TDI passat compared to the picture at the beginning of this thread and mine was missing both 72 relays and the 110 relay. The relay in the slot where 103 should be for the glow was some taller one with like (7) spades on it? part number was nella 90987500.

I would look at the function of those relays; what to they operate? Are there functions that are non-operational on your car?

Search for member g60ing: He has a thread about swapping TDIs: At the bottom of the thread is a link to schematics for A3/B4's.

I checked the main fuse up on the firewall above the fuse box and the fuse was good.

The GP fuse, right?

With the 103 relay out and the coolant temp wire hooked up the glow light on the dash goes on and off in about 1-2 seconds and with the coolant temp wire disconnected it stays on for about seconds so that all seems right.

You are missing a number...how long does the GP light stay on, with the CTS plugged in?
If the GP light stays on for >10 seconds, operation appears normal.

With the weird Nella relay installed in the 103 relay slot I do get power to all (4) of the glow plug harness connections but the glow dash light does not go out at all.

Is this after turning the key on? With the CTS plugged in or unplugged? Keep in mind, the GP light means "wait to start". The GP power will continue with the light off, so long as RPM <2500, and coolant temp is <70F or so.

With the weird Nella relay installed in the 103 relay slot I do get power to all (4) of the glow plug harness connections but the glow dash light does not go out at all.

I'm assuming I need to go get the correct 103 relay but wanted to know what the 72 and 110 relays do? My car is very hard starting and I want to make sure the glow system is working correctly.

I would check idparts.com for the correct 103 relay.

Tony

 

[racerjim]

Yes, I checked the GP main fuse up under the dash and it was good.

With the CTS plugged in and the nella relay out when the ignition is turned on the GP dash light goes on and off in abour 1-2 seconds. With the CTS unplugged and the nella relay out when the ignition is turned on the GP dash light stays on for about 20 seconds and then goes out.

With the nella relay plugged in with the above scenarios the GP dash light does not go out; it stays on constantly. I realize the GP power will stay on until certain engine parameters are met but the dash light should go off eventually, right?

I'll try swapping in my 103 relay from my other 1996 Passat TDI and see if it does the same thing.

 

[drozia]

I wonder that if I take off relay 103 while car is running what will happens?

 

[Lug_Nut]

Nothing. The motor will continue to run if it was already running.
It may not run as smoothly, and the unburned emissions might be higher, until the engine is up to operating temperature, but once the glow plug circuit is turned off (opened) by the ECU, additional openings in the circuit (removal of the relay) will have no additional effect.

 

[drozia]

Nothing. The motor will continue to run if it was already running.
It may not run as smoothly, and the unburned emissions might be higher, until the engine is up to operating temperature, but once the glow plug circuit is turned off (opened) by the ECU, additional openings in the circuit (removal of the relay) will have no additional effect.

Dear Friend,
I have a problem with my 1999 year of Seat Cordoba TDI AHU engine 90 hp. Car stops or engine shut off the gas suddenly in any time while running..I want to start engine again but glow plug lamp does not blow up and engine works hard. There is no problem with cold start. GP lamp flash half a second. When engine warm up this problem begins. Engine first shakens then stops..GP light does not appear when it stops. If I start again light fades a long time and I dont wait and engine starts hardly or not start. After a while car starts normally. Then stops in any time when running on highway at any speed or in city trafic. When this problem occurs in running I take out 103 relay but nothing changes. But I realised one thing that a constant noise comes from relay 103 like as "tik tak". As though noise comes from contacts of relay is it normal? I dont know what should I do. . May this relay 103 cause this problem?

 

[rdkern]

Almost sounds like your "main power relay" is occasionally failing. This is relay 109 in the US, not sure if the same number is on the Seat. Sometimes they start to fail when warm, and give the symptoms you describe.

 

[drozia]

Almost sounds like your "main power relay" is occasionally failing. This is relay 109 in the US, not sure if the same number is on the Seat. Sometimes they start to fail when warm, and give the symptoms you describe.

Yes I thought that and I replaced a new one, but nothing changed..

 

[Lug_Nut]

The glow plug relay should not cycle on and off with a clicking sound.

If the engine and coolant is cold (less than about 10C), the relay should turn on once (close the contacts) when the key is turned, and hold the contacts closed. The lamp will turn on during this time and will turn off when a suggested wait time has passed.
If the key is not turned to the start position, the glow plug relay will remain closed for about three times the lamp duration, and then the relay will open.

If the key is turned to the start position and the engine is put in motion, the glow relay will turn on, and will remain on, until the coolant is above 50C OR if the engine speed is more than 2,500 RPM. There may be a clicking noise if the engine speed is changed from below 2,500 to faster than 2,500 and the coolant temperature is less than 50C. Other than this there should not be any clicking noise from the glow plug relay. The lamp is not illuminated during this time.


If the engine is warm (50C or more), the glow plug relay will not turn on.


The problem of the engine stopping while the car is being driven is not related to the glow plug relay. If the clicking sound is certain to be from the glow plug relay the electrical control circuit should be tested.
My suggestion is to confirm a sufficient earth ground of the engine computer as that controls both the glow plug relay and the fuel pump.

 

[drozia]

The glow plug relay should not cycle on and off with a clicking sound.
If the engine and coolant is cold (less than about 10C), the relay should turn on once (close the contacts) when the key is turned, and hold the contacts closed. The lamp will turn on during this time and will turn off when a suggested wait time has passed.
If the key is not turned to the start position, the glow plug relay will remain closed for about three times the lamp duration, and then the relay will open.
If the key is turned to the start position and the engine is put in motion, the glow relay will turn on, and will remain on, until the coolant is above 50C OR if the engine speed is more than 2,500 RPM. There may be a clicking noise if the engine speed is changed from below 2,500 to faster than 2,500 and the coolant temperature is less than 50C. Other than this there should not be any clicking noise from the glow plug relay. The lamp is not illuminated during this time.
If the engine is warm (50C or more), the glow plug relay will not turn on.
The problem of the engine stopping while the car is being driven is not related to the glow plug relay. If the clicking sound is certain to be from the glow plug relay the electrical control circuit should be tested.
My suggestion is to confirm a sufficient earth ground of the engine computer as that controls both the glow plug relay and the fuel pump.

Thanks for your reply. So how can I observe earth ground connections? where are they placed? and an other case is engine 00522 coolant temparature sensor (G62) -29 10 short to ground indication. From your suggestion I also think so there is a ground connection softening at any point but which? how many ground point are there?and where are their localications?
An other point that interior air circulation doesnt works like as there is a vacuum leak what else..is there a vacuum pump? and if exists where is it?
Thanks

 

[TonyJetta]

If you had a ground fault, you would have more codes.

Replace the Coolant Temperature Sensor; that's all you should need to do.

Tony

 

[Lug_Nut]

Many of the engine sensors are grounded to each other and then to common connections to the auto chassis is used to complete the circuit. I'd also expect to see many intermittant errors, but they'd be open, not short to ground.
However, the short to ground of the temperature sensor may be the cause of the glow plug relay clicking noise. A sensor that is shorted to ground would be interpreted as a coolant temperature at normal operating range. If the glow plugs were operating, and the sensor was briefly shorted to ground, the relay would turn off and then back on.


A vacuum chamber is used to pull closed a flap to close the flow of external air and to open a recirculation air flow path. The vacuum chamber is operated by an electric solenoid valve.
In the early TDI in the US, specifically the 1Z and AHU Passats, this solenoid valve would become stuck usually by metal rust, and not change state to allow the vacuum to the chamber. Replacement of this solenoid operated air valve is usually the remedy for no recirculation.
I presume that your Seat has a similar arrangement

 

[drozia]

Many of the engine sensors are grounded to each other and then to common connections to the auto chassis is used to complete the circuit. I'd also expect to see many intermittant errors, but they'd be open, not short to ground.
However, the short to ground of the temperature sensor may be the cause of the glow plug relay clicking noise. A sensor that is shorted to ground would be interpreted as a coolant temperature at normal operating range. If the glow plugs were operating, and the sensor was briefly shorted to ground, the relay would turn off and then back on.


A vacuum chamber is used to pull closed a flap to close the flow of external air and to open a recirculation air flow path. The vacuum chamber is operated by an electric solenoid valve.
In the early TDI in the US, specifically the 1Z and AHU Passats, this solenoid valve would become stuck usually by metal rust, and not change state to allow the vacuum to the chamber. Replacement of this solenoid operated air valve is usually the remedy for no recirculation.
I presume that your Seat has a similar arrangement

So how do you explain engine coolamt temp. of 136.8 C in the morning cold engine before start? If I loose connection from sensor it shows normal temp. what it is usually matchs to air temparature

 

[Lug_Nut]

You have VCDS. It indicates a fault with the coolant temperature circuit.
Your reading of 137C when the engine is cold indicates a fault with the coolant temperature circuit.
Your report that an open circuit ("..loose connection from the sensor...") indicates nearly air temperature, not a sub-zero temperature. That also indicates a fault with the coolant temperature circuit.
Your report of the glow plug relay clicking could be caused by a faulty coolant temperature circuit.

You might have a failing wiring harness, but because the temperature sensors are known to fail, and a sensor is more quickly replaced with a new one than tracing every electrical wire, I'd suggest that the temperature sensor should be replaced.

 

[drozia]

You have VCDS. It indicates a fault with the coolant temperature circuit.
Your reading of 137C when the engine is cold indicates a fault with the coolant temperature circuit.
Your report that

("..loose connection from the sensor...") indicates nearly air temperature, not a sub-zero temperature. That also indicates a fault with the coolant temperature circuit.
Your report of the glow plug relay clicking could be caused by a faulty coolant temperature circuit.

You might have a failing wiring harness, but because the temperature sensors are known to fail, and a sensor is more quickly replaced with a new one than tracing every electrical wire, I'd suggest that the temperature sensor should be replaced.

So I Understand that a failing wiring harness is caused by sensor itself. Coolant temparature circuit faulty occurs by sensor ok. Thanks and I will replace with a new one. I only wonder that when I fixing quickly it , will be lots of coolant leakage?

 

[TonyJetta]

You will have some leakage.

Yes: What your arrow points to, IS the coolant temp sensor. I would also replace the o-ring that seals it.

Tony

 

[Lug_Nut]

So I Understand that a failing wiring harness is caused by sensor itself. Coolant temparature circuit faulty occurs by sensor ok. Thanks and I will replace with a new one. I only wonder that when I fixing quickly it , will be lots of coolant leakage?

The sensor is a part of the complete circuit. The wires themselves may be fine, but if a wire is broken or if the sensor is broken makes no difference, the circuit is incomplete.
The symptoms you describe indicate that some part of the circuit is at fault. The sensor is not only the most likely cause, but it is also the most easily replaced.

 

[slocorridor]

B4 GP harness - engine side.

sorry if wrong thread, but could not find B4 engine multi-pin discussion. photo shows connector from LH side.

Which wires for the GPs? AND, where does that factory splice go? splice looks like blk 10?gauge splitting to two blk 14g?... I thought I recalled reading the black wires run the plugs, guessing the red wires run to the alt?
Hoping this post will help others, don't guess I'm the last newbie to trade the factory harness with the new. Goal is to eliminate any mechanical connection here in favor of some silver solder.

Cheers -

 

[TonyJetta]

slocorridor, you have the correct connector, but something doesn't look right.

And, no, the alternator wires (small or large) do not pass through that connector.

I'll look to see if I can find a clear picture for you to reference.

Tony

 

[slocorridor]

GP troubleshooting - what's next

The heavy red wires in the multi-pin are the glowplugs. they pin out on the rearmost two flat spade pins in the connector on my 97. Soldered in the new harness and replaced relay 180, still have CEL...
Update - cleared the code in VCDS and no issues since.

cheers -slc

 

[TonyJetta]

Start with the GP 101 thread.

Post back any questions or issues. You are likely better off starting your own thread, in the A3/B4 section: You'll get more specific help there.

Tony

 

[drozia]

Many of the engine sensors are grounded to each other and then to common connections to the auto chassis is used to complete the circuit. I'd also expect to see many intermittant errors, but they'd be open, not short to ground.
However, the short to ground of the temperature sensor may be the cause of the glow plug relay clicking noise. A sensor that is shorted to ground would be interpreted as a coolant temperature at normal operating range. If the glow plugs were operating, and the sensor was briefly shorted to ground, the relay would turn off and then back on.


A vacuum chamber is used to pull closed a flap to close the flow of external air and to open a recirculation air flow path. The vacuum chamber is operated by an electric solenoid valve.
In the early TDI in the US, specifically the 1Z and AHU Passats, this solenoid valve would become stuck usually by metal rust, and not change state to allow the vacuum to the chamber. Replacement of this solenoid operated air valve is usually the remedy for no recirculation.
I presume that your Seat has a similar arrangement

So where is that selonoid valve located at? What is the item number do you know?

 

[myvwisfast]

HOLY CRAP! Thanks to this thread, I've finally found the solution to an issue the dealer couldn't even figure out.

My 97 A3 had a second GP relay in position #12. Starter engaged and glow plug indicator on dash was dimly lit when clutch pedal depressed, tripping CEL. SOOOOO FRUSTRATING!

Previous owner spent $1600 at the dealer chasing this issue, to no avail.

Thanks, Lug Nut.