What are these three things?!

[Jobe]

These connectors pop off kinda like spark plugs but when I took them off the plastic part basically disintegrated. I need to replace them but don't know what they do or are called.
2005 Jetta Wagon TDI BEW

http://imgur.com/a/p1hlgrd

http://imgur.com/a/fKRHq1E

They are on the top of the driver's side of the engine.

Thank you so much!

 

[IndigoBlueWagon]

Those are coolant glow plugs. They're supposed to operate when it's cold out to help the engine warm up faster. If they're not working they don't throw a code, however.

 

[Nuje]

I wouldn't be surprised if more than half of the ALH cars still running around out there have these not functioning.

I suppose those coolant glow plugs do help get the coolant up to temp, but they are so inconsequential that the cars with the automatic transmission didn't even have them (the automatic transmission itself, though, does throw off heat so I guess they swapped the glow plugs for running coolant through the automatic).

Anyway, where you live on the west coast, without real winter, I doubt you'd even be able to tell if they were or weren't working. So, motor on.

 

[P2B]

The disintegrating harness can be a fire hazard - actual flames in one of ours.

Cut the harness and tape it out of harms way.

 

[GlowBugTDI]

2005 Jetta Wagon TDI BEW

Not a 2005 and not a BEW. 99.5-03 jetta or golf. Or a 98-2003 beetle. This is an ALH engine.

 

[jayb79]

My 2000 NB had them. My current Golf has them on manually controlled switches. Great to have in cold weather in town driving. I believe they were in all manual ALHs.

 

[AndyBees]

Nujue, and the MK4s (and maybe others) with an automatic transmission also have fuel coolers on the return hose/pipe back to the fuel tank.

The ECU doesn't monitor those Coolant Glow Plugs.

 

[JB05]

The two controlling relays for the coolant GP's are monitored be the ECU. Forget where I read that.

 

[gmenounos]

They're controlled by the ECU but not monitored by it.

 

[Vince Waldon]

To be crystal clear:

- the two coolant heater plug relays are SOMEWHAT monitored by the ECU. If you mess with the relays enough (say, by paralleling your own manual override wiring thru diodes, for example) the ECU will detect it... BTDT, as we speak
- the coolant heater plugs themselves are NOT monitored by the ECU

 

[gmenounos]

Yeah, sorry, by "they" I meant the plugs, not the relays. The ECU controls (and sees) only the input to the relays, not the outputs.

 

[Vince Waldon]

Yup, all good, and that's a good way to explain it: the ECU sees the inputs of the relay(s) but not the outputs.

I diode-ORed a manual dashboard switch in parallel with the ECU's inputs to the relay, and the sneaky ECU notices the 0,7V drop. It sees some things all too clearly and ignores a bunch of other actually-useful stuff.

 

[AndyBees]

So, if and when the ECU detects whatever it is programmed to detect with the Coolant GPs, does the CEL come on? If so, what is the DTC that comes up on a scan? Or, are they on that long list of things that cause the Glow Plug light to flash?

 

[Vince Waldon]

In my case my modified wiring (manual activation switch on dash for one plug or all three) results in no CEL but two codes that I've not bothered to concern myself with further, as the system works as designed:

P19460: Relay for preheating of coolant (J359) P3004 - 000 - open or short to ground
P19462: Relay for preheating of coolant (J360) P3006 - 000 - open or short to ground

Here in the frozen Canadian tundra amongst the igloos the plugs make a noticable improvement to defrost times, but do load up the alternator when all three are on.

 

[ninedee_golf_tdi]

This has probably been asked and answered 100 times. But..... where are the j359/j360 coolant glow plug heater relays ? On my 2002 01m wagon they are "not" by the brake booster, although the mount attached to the fire wall is there. Thanks.

 

[gmenounos]

This has probably been asked and answered 100 times. But..... where are the j359/j360 coolant glow plug heater relays ? On my 2002 01m wagon they are "not" by the brake booster, although the mount attached to the fire wall is there. Thanks.

Coolant glow plugs should only be present on manual transmission (02J) cars.

 

[ninedee_golf_tdi]

You beat me to the edit I was going to make. I realize the 01m equipped cars don't have the coolant glow plugs, but I still am getting the codes for j359/j360 being intermittent. Baffling to say the least.

 

[gmenounos]

Is your ECU coded for a manual transmission?

 

[ninedee_golf_tdi]

Coded 00001. Good try though.

 

[John Wesley Hardin]

Those are coolant glow plugs. They're supposed to operate when it's cold out to help the engine warm up faster. If they're not working they don't throw a code, however.

Holy Shiite ! How do you know if they are functioning ? I have one , never gave it a thought . I need heat in the cabin wonder if it helps if its working

 

[AndyBees]

The 2002 model A4s with a 5-speed have the two Coolant Glow Plug Heater Relays mounted under the dash on the relay panel.
This is where they were on the 2002 wiring harness I got with the engine from Jimbote who got it from MrGutWrenche's wrecked Jetta in 2007.
I included them with the conversion install in my 84 Vanagon.

 

[ninedee_golf_tdi]

Just about identical symptoms as Joester had in 2015. ECU still thinks I have a 5 speed, get a weird 18065, 17946 and 19459. Time to try a different ECU. https://tinyurl.com/3st35r6v

 

[John Wesley Hardin]

Coolant glow plugs should only be present on manual transmission (02J) cars.

How do you know if they are working? Or would it just be simpler to replace them ? In my car they have probably never been replaced in 330'000 miles

 

[P2B]

How do you know if they are working?

If the harness is intact and the plug resistance is under 5 ohms they should be working - not that you care in your climate.

 

[John Wesley Hardin]

If the harness is intact and the plug resistance is under 5 ohms they should be working - not that you care in your climate.

If the harness is intact and the plug resistance is under 5 ohms they should be working - not that you care in your climate.

If the harness is intact and the plug resistance is under 5 ohms they should be working - not that you care in your climate.

Well , in South Texas we do experience butt freezing temperatures 30 degree and below and snow believe it or mot.. So for me on my drive I want heat and right away. If this will help my cabin temp Im all for it !

 

[ninedee_golf_tdi]

Just about identical symptoms as Joester had in 2015. ECU still thinks I have a 5 speed, get a weird 18065, 17946 and 19459. Time to try a different ECU. https://tinyurl.com/3st35r6v

I swapped ecu's and the problem of my ecu thinking I had a 5 speed when it was an 01m is gone, as are the two other codes. I generally scoff at folks who jump at accusing the ecu of being bad, but in my case as with Joester's, it was definitely the cause.

 

[[486]]

Holy Shiite ! How do you know if they are functioning ? I have one , never gave it a thought . I need heat in the cabin wonder if it helps if its working

they don't do anything
read up on when the ECU has the idle raised, that is also when these are being run
iirc it's something like 2 minutes after startup that they shut off no matter what, and only below some coolant temp that you probably never experience in TX (because it is very rare even in mn)

 

[Sting]

they don't do anything
read up on when the ECU has the idle raised, that is also when these are being run
iirc it's something like 2 minutes after startup that they shut off no matter what, and only below some coolant temp that you probably never experience in TX (because it is very rare even in mn)

This is good to know... my spare engine is from an automatic ALH. I was thinking about swapping over that flange that carries the coolant glow plugs, but honestly, I don't think I will now. Doesn't seem like much of a benefit for 2 minutes.

 

[John Wesley Hardin]

they don't do anything
read up on when the ECU has the idle raised, that is also when these are being run
iirc it's something like 2 minutes after startup that they shut off no matter what, and only below some coolant temp that you probably never experience in TX (because it is very rare even in mn)

Then why bother, I'll just put a burn barrel in the front seat

 

[J_dude]

Then why bother, I'll just put a burn barrel in the front seat