October 18

2002 Jeep Grand Cherokee, Heater Blend Door Replacement

Auto Repair, Jeep


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.

Mark: Do you have some pictures of that?

Bernie: We got pictures. I love showing this kind of stuff. It's super interesting. We'll just go back and we'll start. This is our Jeep 2002 Overland. It's a little bit of an older vehicle, but nice for it's year and age. That is a view of the instrument panel and the dash removed. That's what you got to do to change this particular blend door. It's a lot of work as you can see. The body if you just take the time to savour the photo for a minute. If you look in the top right there's a few kind of grey items, square items. That's the heater box. That unit, that's actually been re installed but we have to remove that unit, and that's where the blend door's located along with the heater core, the evaporator core, and a whole bunch of other bits and pieces. You can see the steering wheel sort of line in the bottom left corner. It's sitting upside down. It's that round, that brownish coloured piece. Then on the actual seats which are on the right, which you can barely tell are seats, that's the dash. That's the thing you're looking at.As you can see, this is a huge amount of work to take apart. Our next photo, this is the actual blend door that we replaced. It's two separate doors that operate. You see a couple of red arrows there. They point to where the motors engage the blend doors, and you can see they're broken. Over time what happens is when the vehicle turns on, it starts, and the climate control system doesn't check. It actually actuates every door, so there's blend doors. There's the doors that control the up and down air flow. It operates all these doors just to make sure the whole system's operating, and then if there's an error, it'll send something back into the system.Every time these doors are operated, they're moved a lot more often that then probably need to be, but over time it breaks. That's what the real problem was with this vehicle. We changed the blend doors, put the motors back in, and away we went. Now there was a couple other things. We can get into that. We did actually find a couple of other things when we had the heater box apart. I'll share those photos, too. Just give me a second to get back to the screen sharing. Where are you?Inside the heater box, there's also as I mentioned the evaporator core and the heater core. The evaporator creates the cold for the air conditioning. The heater core creates the heat for the heating system. Of course, we had the heater box apart so we found a couple of interesting things. If you notice on the right hand side, there's a bunch of greeny and the top a bunch of ugly green. That's antifreeze that's leaked out of the heater core. Now this vehicle didn't actually have a ... There was no client complaint of a heater core problem, but nonetheless, this was starting to leak so this was a great time to replace the heater core. It was out. No extra charge for labor, just the part. Then we found the evaporator core also had a very small leak. Again the red arrow points to that.You can see that sort of oily film and a bunch of dirt build up. That is actually a very small minute evaporator core leak. You could even smell the refrigerant oil in the area. Again, the air conditioning worked fine before we started. It was nice and cold, but this would have created problems, and we would have had to pull the whole thing back out again. It was a very good time to. It was an expensive repair, but very fortuitous for our client that we kind of dealt with everything.

Mark: Well, how did all the work once you were all done. That's a tremendous amount of work.

Bernie: Yeah it was good. There was nice heat, cold air in this vehicle. The temperature was right on the right hand side and good on the left hand side and everything was good control. Everything was like it's supposed to be, so restored to normal, and the owner was happy.

Mark: There you go. Another successful repair by Pawlik Automotive in Vancouver. Vancouver's best auto service experience, 17 time winners of best in Vancouver as voted by their customers. Reach them to book at 604-327-7112 or check out their website at pawlikautomotive.com. We have a few years now of these kind of videos on there, so there's a ton of information plus all the stuff that Bernie's created himself. Check it out. Pawlik Automotive. Thanks Bernie.

Bernie: Thanks Mark. Talk to you soon.

About the author 

Bernie Pawlik

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