Idle control unit (ICU) in 86-91 Vanagons. Where is it, how do I replace it?
Replacing the ICU requires some dexterity, attention to detail, and patience; but no special tools. The only part you have to remove to get to the ICU is the right rear tail light lens. Here is how you can find it and replace it:
1) Remove the four screws holding the right (passenger) side tail/stop/reverse/turn signal lens to the body and move the assembly out of the way.
2) Look straight back with a flashlight and you will see the control unit siting with the plastic housing pointing up. On Syncro models, it is a bit trickier to see and replace because the fuel filler conduit is right in the way.
3) Using one hand and working blindly, pull straight up on the unit AND the plastic electrical plug that it plugs into; do not try and unplug the unit from the plastic electrical plug at this point. The plastic electrical plug that it plugs into is dove-tailed into a separate plastic bracket, which is the part screwed to the body. Wiggle the whole thing while gently pulling straight up until it comes off the bracket.
4) Once you have separated the plastic electrical plug from the plastic bracket, you can pull the ICU and plug closer to the tail light lens opening in the body with fuel injection wiring harness still plugged into it. Now you can use both hands to unplug it from the harness. It is helpful to gently pry the unit off the plastic plug with a flat screwdriver.
5) Be careful when you plug the new ICU back in that none of electrical connectors are pushed out of the electrical plug-that is a common mistake that leads to the misdiagnosis of a good ICU as being bad. Once the new ICU is plugged in, you will have to work with one hand, blindly to slide the plastic plug dove-tails back into the matching dove-tail slots in the plastic bracket.
They were originally made for Volkswagen by VDO, but have been discontinued and are no longer available new. This unit is rebuilt (see rebuilding info below) and sold on an exchange basis, with an additional $100 core deposit added to the price listed. You are required to return your old rebuildable unit or forfeit the $100 core deposit.
Please call our customer service team for a return authorization number prior to shipping your core: (888) 469-3789.