Glow Plug Harness: Powerstroke Parts on a VW TDI

I’ve been enjoying my 2005 Passat Wagon TDI for nearly two years, now. Like my Jetta, it’s another little diesel in my fleet. The engine is the BHW code, making it a Pumpe Duse engine. It’s not as efficient as the Jetta’s ALH engine, but it still gets me into upper 30s, but with a more comfortable family machine with a leather interior. When I bought the car it had a dead automatic transmission, so I was able to get a deal on it. I dragged it home and got to work on swapping the transmission for a standard using used factory parts sourced from Dutch Auto Parts in the Netherlands. Today you wouldn’t know that it came with an automatic transmission in it, because it looks completely stock.

This is the inexpensive part I used to replace my worn-out glow plug harness on my Passat TDI.

This is the inexpensive part I used to replace my worn-out glow plug harness on my Passat TDI.

The car now has 200,000 miles on it and I started getting the dreaded “EMISSIONS WORKSHOP” messages every time I started the engine. Pulling the codes, I found out that I had an open circuit at one of my glow plugs. I checked the glow plug and found that it had good continuity, so I knew it was the harness. VW charges too much for glow plug harnesses, and I must say that I didn’t bother to price it this time around. I wrote up an article a while back showing how to use R/C bullet connectors to make a glow plug harness rather than spending $80 on a factory part. Some of you told me that you’ve used the Powerstroke 6.0 harnesses you’ve bought on eBay, so I decided to give this a try. I found this one on eBay for $19.99. In case that link is dead, the seller was calvinvo, and the title was “2004 – 2010 Ford 6.0L Powerstroke Diesel Glow Plug Harness Left Driver Side.”

It came fairly quickly after I ordered it. I got started by chopping off the connector and peeling back the convoluted tubing. THEN, I realized that I’d like to start blogging again and took a snapshot of it. I should have taken a snapshot first, but this still gives you an idea of what it looked like.

I checked the four wires with an ohmmeter to see which color went to which connector. Using the one closest to where the connector used to be for the #1 cylinder, the codes are yellow for #1, red for #2, white for #3, and blue for #4. I tried snapping one of them onto the #1 glow plug after I removed the original harness, seeing that the large plastic caps would allow the couplers to snap onto the glow plugs.

Note that the black coolant tube has dimples near the glow plugs to make room for the stock harness.

Note that the black coolant tube has dimples near the glow plugs to make room for the stock harness.

I made new solder connections and covered them in heat-shrink tubing. Then, I went to install the harness and found that #3 and #4 didn’t fit. I realized that a coolant tube runs quite close to the head on the BHW engine, keeping the large plastic connectors from sliding into place. To make room for the stock harness, I noticed that VW put dimples in this tube.  I wasn’t going to enlarge the dimples or relocate the tube, so I got out my rotary tool and used a cutting disk to remove material from the underside of the plastic connectors for glow plugs #3 and #4.

These plastic connectors have o-rings for the Powerstroke application that must be used to keep water from getting into the cavities where the glow plugs are on that engine. The VW TDI engines have glow plugs that are exposed to the air, so there’s no need for this much plastic. I trimmed them back until I could snap the connectors in place.

I trimmed the glow plug connectors on cylinders #1 and #2 so that they would fit alongside the coolant tube that runs past the BHW head.

I trimmed the glow plug connectors on cylinders #1 and #2 so that they would fit alongside the coolant tube that runs past the BHW head.

Success! I’ve been able to clear the code and I no longer create an embarrassing blue haze hanging in the air when I start the cold engine on a cold day!

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Comment (1)

  1. Mark-A-Billy

    By the way, everybody, the cheap Powerstroke harness I had didn’t hold a very good crimp and I wound up with open circuits a couple times. Trying to put a little crimp on these just made things worse. I wound up using 4mm bullet connectors from model airplane supplies and some wire.

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