Had my GTI throw an error code P0118 over the weekend and even though the temp gauge was reading fine and the outside temps were cold and rainy the electric fan ran at full tilt after turning the car off so a quick browsing of the forums told me my ECT was most likely bad so I ordered a new one and went to install it this morning.
Pulled the engine cover and immediately found what was most likely the cause of the error code.
I am guessing a rat got up in the engine bay over the holiday break when the car sat idle for a few weeks and did the damage. Even though I knew I had to fix the wires I went ahead and swapped out the ECT sensor while I was in the neighborhood and went about trying to fix the wiring.
As this was my only transportation at the moment I had to fix it with what I had on hand which fortunately included a complete wiring harness from a Mk7 GTI. I found an identical plug on the Mk7 harness but the wire colors were all wrong and I didn't want to ruin that harness just to cobble something together so I thought if I could pull the terminals out I might be able to replace the existing wires.
Found a video on how to remove the terminal but didn't have the proper tool but did have some free time and a new Bosch cordless rotary tool so with a little luck some pliers and a spare hair pin I now had an impromptu terminal release tool.
Once I had the terminals out I saw that there was little chance I could remove the existing wire and crimp in some new stuff without destroying things but there was just enough wire left to strip, solder and shrink some extensions onto and reinsert into the connector. THe original colors were Pin1:Green Pin2:Brown but I only had Green and Black/Yellow wire handy so as long as the Green matched up I figured the other wire should be obvious...lol
I am sure someone will point out that solder isn't always the best option in a high vibration environment and I agree but I had so little wire left that it was a situation of necessity. I may order new terminal plugs and do it over at a later date though.
Once I had new lead wires on the connector I had to pull apart the wiring harness to get enough slack wire to do the patch. Again due to what I had handy I just did a strip, solder and shrink job figuring that if I go back and replace the connector terminals I can fix this part as well.
And to make myself feel a bit better I used some spare wire loom material and some electrical tape to make the install look more professional. Other than that tiny bit of green wire showing through the split in the factory loom it looks better than stock.
Other than the fact that I recently realized I forgot to put the purple secondary retaining clip back into the connector it went about as smoothly as I could have hoped for. Still deciding if I should fix it now or just order the terminals and fix everything at once.
One tip is that the amount of coolant that spilled out when I pulled the ECT surprised me so if I had to do it again I would try and park the car with the driver's side up hill to try and minimize the loss.
Pulled the engine cover and immediately found what was most likely the cause of the error code.
I am guessing a rat got up in the engine bay over the holiday break when the car sat idle for a few weeks and did the damage. Even though I knew I had to fix the wires I went ahead and swapped out the ECT sensor while I was in the neighborhood and went about trying to fix the wiring.
As this was my only transportation at the moment I had to fix it with what I had on hand which fortunately included a complete wiring harness from a Mk7 GTI. I found an identical plug on the Mk7 harness but the wire colors were all wrong and I didn't want to ruin that harness just to cobble something together so I thought if I could pull the terminals out I might be able to replace the existing wires.
Found a video on how to remove the terminal but didn't have the proper tool but did have some free time and a new Bosch cordless rotary tool so with a little luck some pliers and a spare hair pin I now had an impromptu terminal release tool.
Once I had the terminals out I saw that there was little chance I could remove the existing wire and crimp in some new stuff without destroying things but there was just enough wire left to strip, solder and shrink some extensions onto and reinsert into the connector. THe original colors were Pin1:Green Pin2:Brown but I only had Green and Black/Yellow wire handy so as long as the Green matched up I figured the other wire should be obvious...lol
I am sure someone will point out that solder isn't always the best option in a high vibration environment and I agree but I had so little wire left that it was a situation of necessity. I may order new terminal plugs and do it over at a later date though.
Once I had new lead wires on the connector I had to pull apart the wiring harness to get enough slack wire to do the patch. Again due to what I had handy I just did a strip, solder and shrink job figuring that if I go back and replace the connector terminals I can fix this part as well.
And to make myself feel a bit better I used some spare wire loom material and some electrical tape to make the install look more professional. Other than that tiny bit of green wire showing through the split in the factory loom it looks better than stock.
Other than the fact that I recently realized I forgot to put the purple secondary retaining clip back into the connector it went about as smoothly as I could have hoped for. Still deciding if I should fix it now or just order the terminals and fix everything at once.
One tip is that the amount of coolant that spilled out when I pulled the ECT surprised me so if I had to do it again I would try and park the car with the driver's side up hill to try and minimize the loss.