Out of the blue, my heater doesn't seem to want to switch from defrost to the middle vents, will switch the recirc and floor vent doors just fine, and will switch back to defrost. On occasion it will bring in the middle outlets the first time switching on, but that has gotten rare the last few days. Looking at the manual, it appears as if it is either the panel actuator or the heater control panel.

Of course, the manual starts out with for replacing the actuator, " remove heater box assembly"

Couple of questions for those of you who have been down this road.

1.) what is the likely hood of it just being the control module?

2.) that actuator looks like you might just be able to get at it by removing the instrument cluster ( fair warning, I haven't looked under there yet ), has anyone replaced that actuator without pulling the dash?

Thanks.

 

I had my dash apart last month for evap/heater cores, albeit on a 98 that may be a bit different then a 97. BUT on mine I was getting intermittent control like you describe, and while I had the dash out it does look like you could get to it with the intrument cluster and/or radio out... but after laying the dash down I'd rather do that any day rather then try to pull the cluster or radio to get to it. Mine turned out to be a broken flapper, actually the little shaft that the linkage connects to. Jerry rigged a new peice of linkage with a screw into what was left of the shaft to get it working again. I honestly don't know how it was working at all to begin with but it did somehow.

 

To close the loop on this one, it turned out to be a bad vacuum actuator, all fixed now, without pulling the stupid heater box.

I had plenty of room to get to it by pulling the knee bolster, then the metal dash reinforcement behind it, in all probably 15 metal screws. The actuator is on the right hand side of the opening, not hard at all to get to, remove 2 screws, the vacuum hose, then the trick is getting it off the lever without breaking it. Fortunately, I have a spare heater box at home to practice on. The arm that pulls the door just snaps over the lever, the lever has 2 legs that pop out when the arm goes past. Try as I might, I couldn't depress the legs enough to slide past, so after some studying and contemplation, the solutions became obvious. What you do is pull down slightly while you gently lever the arm away from the pin, this starts one edge over the protrusion on one side, then you use the rid to stay on the one while you gently push up and get it over the other one, I wiggled it just a bit, and she popped right off. I can;t stress enough, GENTLE! You sure don't want to break the thing.

I actually had a harder time getting the new one over the pin than getting the old one off.

Total start to finish was less than 30 minutes.

BTW, I grabbed an actuator out of a 94 for my 97, same thing, so it looks like they didn't change anything for the first few years!