How to make a $2 glow plug harness.

[koolpunjabi]

I didn't want to spend 60$ for a failing 2 wire glow olug harness for my Jetta 2000 TDI. So here is what I did. It cost me only $2 and it is working perfect for more then 6 monthe now. I used a small piece 14-2 copper electrical wire, 4 female and 2 male 14-16AWG connectors, some electrical tape and some wire loom to cover the wires.
First, cut the wires to approximate size laying next to oem harness.
http://pics.tdiclub.com/showphoto.php?photo=81348&title=img-20111118-123633&cat=500
Next, solder the joints for good connection and apply electrical tape on them.
http://pics.tdiclub.com/showphoto.php?photo=81349&title=img-20111118-123703&cat=500
Then connect the 14-16AWG female connectors at the four ends which will go on the glow plugs. This is what I used. The size of these connectors fits the glow plugs perfectly.
http://pics.tdiclub.com/showphoto.php?photo=81350&title=img-20111118-123851&cat=500
In the end, I used pieces of wire loom and electrical tape for weatherproofing the new harness.
http://pics.tdiclub.com/showphoto.php?photo=81351&title=img-20111118-130639&cat=500
I also connected 2 female connectors on the car side wires.
Here is my $2 glow plug harness installed in my car. It is working perfectly for more then six months now.
http://pics.tdiclub.com/showphoto.php?photo=81352&title=img-20111118-131446&cat=500

WARNING: DO IT AT YOUR OWN RISK. I AM NOT RESPONSIBLE FOR ANY DAMAGE DONE TO YOU OR YOUR CAR.

 

[procupine14]

Not a bad idea, especially if you are on a budget. This would probably interest a lot of people in warmer climates that just want the code to go away and not have to pay for something that they rarely (if ever) use in the first place.

If it has worked for you it might work for others. I commend you on being innovative if nothing else

 

[oldgrey]

That is just what I have been thinking of building for my 2000. I have all the bits in my shop, so faster and way cheaper than buying a harness. The check engine light bugs me when the plugs check out fine by ohms and testing.

 

[HornetHandler]

Well done. And let me congratulate you on not allowing any solder to wick (flow) up under the wire insulation. This is very important as it will cause the wire to workharden and break under vibration.

If the solder connection ever fails may I recommend the next time that you twist the wires together before soldering them? One of the important 10 steps to a good soldered connection is to first ensure you have a good mechanical connection between the parts to be soldered.

Good luck,

Mack

 

[koolpunjabi]

@oldgrey
That was exactley the problem I had. MIL was on every now and then and the plugs checked ok.
@porcupine14
I will be testing this during canadian winter. I was thinking of putting some kind of coating on the exposed part of glow plugs to prevent oxidation.
@hornethandler
Twist and solder is a good idea. If I run into any problem, I will try tht next time.
Thanks.

 

[bjmarler]

TY, Very nice!

 

[shegel]

Thanks I used to just pack the connector with dielectric grease but that only works till the weather warms up. I'll be building one of these at work today. For some reason t thought the factory setup had a sensor or something in it.

are you concerned about the current draw with just using 14 ga wire?

 

[mrGutWrench]

(snip) I will be testing this during canadian winter. I was thinking of putting some kind of coating on the exposed part of glow plugs to prevent oxidation.

__. Dunno it there's enough "shrink" but how about using shrink tube. Shrink it down (heat) until it's tight on the plug. If you have to take it off, just cut it off and throw it away and replace it. If it doesn't shrink down enough on the 14 ga wire, then you could put a cylindrical plug on the wire to expand the area that the shrink fits onto.

 

[derewaj]

I was having harness problems too - seemed like every time the engine shook a little (near stall taking off or a cold start) I would get a GP fault.
I tried cleaning, crimping, a little tin foil stuffed into plug (this worked for a while) and dielectric grease but nothing worked very long until this:

I cut the ends off the harness and crimped/soldered on ring terminals. Then I pulled the GP's and ran a #8-32 die down the top of the plug where the harness normally slid on - it's the right diameter - reinstalled the plugs and used a couple nuts to lock the ring terminal on the GP.

No CEL's since I did this a month ago!!

 

[compu_85]

All the old diesels have threaded connections on the glow plugs.

-J

 

[procupine14]

All the old diesels have threaded connections on the glow plugs.

-J

Seeing as this seems to become a problem as a lot of the newer diesels age it makes me wonder why they stopped doing this from the factory.

 

[compu_85]

It's quicker to assemble a push on connector.

 

[procupine14]

It's quicker to assemble a push on connector.

sigh* fair enough I suppose....

 

[turbocharged798]

It's quicker to assemble a push on connector.

Yes, but you can get heat shrink crimp ring terminals and have a 100% waterproof connection. Butt connectors are not waterproof. I have concerns that the plastic might melt too.

I like the threading the glow plug idea a LOT. I may actually try it on the 99.5. The harness is original and pretty much done for.

 

[compu_85]

*knock on wood* my harness is original too, and still going strong

I have re-crimped the ends twice.

-J

 

[UFO]

Yes, but you can get heat shrink crimp ring terminals and have a 100% waterproof connection. Butt connectors are not waterproof. I have concerns that the plastic might melt too.

I like the threading the glow plug idea a LOT. I may actually try it on the 99.5. The harness is original and pretty much done for.

The threaded connection would probably work well, but regarding butt connectors, these might work fairly well too...

 

[jayb79]

They don't get very hot. I would guess maybe 300f on a real hot day idling in traffic after a hiway run.

 

[turbocharged798]

The threaded connection would probably work well, but regarding butt connectors, these might work fairly well too...

Where do you get those? I have never seen a heat shrink butt connector before.

 

[Croberts]

I admire you guys but for me it was worth it to just buy new. I chased the check engine light about 150k miles ago and a new harness fixed it. Came back this summer and I waited until the cold temps returned. Two of the four glow plugs were bad so I looked at idparts and found that they now offer a combo deal of 4 ALH Bosch glow plugs and a authentic VW 4 wire harness for $109. USPS Priority Mail for $7 and two days later I had my parts. I did the ghetto harness install method and the problem was fixed in short order. I am now ready for the cold Wisconsin winter.

 

[PDJetta]

Fill the butt connector end with RTV silicone sealer.

--Nate

 

[turbocharged798]

Fill the butt connector end with RTV silicone sealer.

--Nate

I was thinking that.

Also I made a mistake, its called a bullet connector, a butt connector has crimps on both ends and joins two pieces of wire.

 

[UFO]

Where do you get those? I have never seen a heat shrink butt connector before.

All the big chain auto parts stores have them. This picture was from AutoZone.

 

[jayb79]

Bulk packaging here:
http://www.amazon.com/Install-HSBFB...=UTF8&coliid=IRD3RRRPSPC1P&colid=Q7KUDT1MSN4P

 

[Keith_J]

The threaded connection would probably work well, but regarding butt connectors, these might work fairly well too...

The glow plug terminals are silver plated. You will have to coat the threads with dielectric grease to prevent corrosion.

 

[WillR]

Can you just combine the 2 wires from the glow plug harness together?
If this would work, this would get rid of the glow plug error light for ever.

Then in the future, if you start to find it starts hard, or runs on 3 cylinders for a second you know it's time to check your glow plugs.

 

[Vince Waldon]

Dunno if it would work... it depends on how the how the drive circuitry works... but in my mind that's like taking the battery out of the smoke detector so that it doesn't warn you about those pesky fires.

OK, not the best example, but if you've ever been stranded during a cold snap by a couple of dead glow plugs you didn't know you had a fault light for bad glow plugs is a feature, not a bug... BTDT back in my IDI days.

 

[WillR]

My A3 started (a bit reluctant, but it started) at 28 deg F. with the fuse blow on the glow plug circuit.

My A4 has been starting on only 3 glow plugs since July. This morning it was 25 deg F.
You don't need a CEL to tell you 1 or more is bad. It will start and miss for a couple revolutions (with the tell tale smoke) when you have 1 or more plugs bad.

but the average TDI driver (Fred's group excluded) needs the light to tell them something is wrong.

 

[csstevej]

If your worried about the GP's check them at every oil change, takes 2 sec's. I've been running on three GP's for close to three years, fourth snapped off in the head and couldn't get it out. Someone had metioned the idea before about connecting the wires together to eliminate the cel light. I've done this, soldered my two wire harness together and pretty much cured my cel gp light due to only three gp's. Some may not agree with this method but everything i tried to do to remove the gp failed so instead of ruining the haed or sending it out for repair i went with this route. It's been about two years with this setup.

 

[WillR]

Thanks Steve. I thought I had read that splicing the 2 wires together would fake out the test circuit.

I think I am going to build my own harness instead of buying one.
I hear the glow plugs are threaded on the wire connectors. I am tempted to throw 2 nuts and washers on them and use spade type connectors instead of snap on connectors. This will eliminate the corrosion problem for good .

 

[jackbombay]

I cut the ends off the harness and crimped/soldered on ring terminals. Then I pulled the GP's and ran a #8-32 die down the top of the plug...

No CEL's since I did this a month ago!!

I did it 5 years ago and have had only had one GP CEL since, and I actually had a bad GP.