2002 Jeep Grand Cherokee, Heater Blend Door Replacement

Bernie Pawlik, Pawlik Automotive Vancouver, BC
http://pawlikautomotive.com (604) 327-7112

Mark: Hi, it's Mark from Top Local. We're here with Bernie Pawlik, Pawlik Automotive in Vancouver. Vancouver's best auto service experience. How you doing today Bernie?

Bernie: I am doing very well this morning.

Mark: We're going to talk about a 2002 Jeep Grand Cherokee with a little bit of a different issue. What was going on with this vehicle?

Bernie: Well, this issue had some ... There was stuff going on with the heating system on this vehicle. It wouldn't blow hot air. It sort of started out originally it would only blow hot air from one side of the vehicle. This is a vehicle that has a dual zone climate control. It's a Jeep Grand Cherokee Overland, so it's a top end vehicle full of luxury on road and off road features. The climate control system wasn't working right. There was too much heat on one side of the vehicle, not enough on the other. It couldn't be controlled properly.

We went to access the vehicle heating system, and we can do this with a scan tool of the computer because it's electronically controlled. We went to access that and that's where we started our procedure.

Mark: That sounds like interesting thing. What was involved after you had gotten into the electronics?

Bernie: We plugged in our scan tool, and there's different ... They're called PIDs, parameter IDs, and so we looked at the different PIDs. We could see that some things weren't reading right and then there's some actual actuator tests we can do on the scan tool. Nothing would respond properly. Things weren't reading right. A little confusing, and we finally determined the actual heating control unit, the actual computer, something was screwed up with that. This is a really expensive part. It includes the panel with all the knobs. It' the thing you see and inside there's a computer as well. We acquired a good used unit because it's an old vehicle. The owner didn't want to spend I can't remember it's like 1,200 or 1,500 dollars for the actual climate control unit. We managed to get a good used one for a fraction of the price.

Put it in, and all the computer end of things were working great, but what we found, then we found the other problems that had probably been there for a long time, and that is we still couldn't control the actual it's called the blend door. The blend door controls the temperature between the air conditioning system and the heating system. The blend door's this little motor twists and turns doors inside. There's a whole bunch of doors inside these vehicles. Most vehicles are like that nowadays. Blend doors couldn't be controlled so that's where we basically have to rip the heater box out and go to the next step of the operation.