trailblazer EXT aux HVAC clicking sound, 9 clicks

[Ben in Kona]

Title says it all, the temp workaround was to remove the #36 fuse in the rear underseat fuse box. Side effect was continuous front seat heater, but it's winter time so not so bad (even in Kona)... I have removed the right rear quarter trim panel (and a lot of others on that side) and the clicking seems to come from the "auxiliary air temperature actuator".. The actuator clicks 9 times at about a 200 to 500 msec repetition rate, then pauses for a click time and repeats.. It looks like the "aux .. control module" should be sending 0 and 12 volts to the "aux air temp actuator module" on pins 4 and 5 (0v & 12v or 12v & 0v depending on whether it should be opening or closing the door) I have not yet determined the air temperature door position (the car is out and about for a few hours (w/o its rear side trim) and I don't yet know how to find the door) I don't yet know if it's the "Aux HVAC control module" sending bogus control signals or if it's the "air temp actuator "itself not sending the feedback position signal correctly.. When the car returns I intend to tap my voltmeter into pins 2 & 1 (the door position potentiometer) with safety pins and see if it's pegged either way. Then pins 4 & 5 to determine if the command control module is stuck.. I don't know the sense of the +/- 12v command vs the +/-5v door open position signal ..

If there's some other easier (or more definitive) way to diagnose the replacement of either the air temp actuator module or the control module Please let me know.

[Hank]

The clicking says itr all-
The actuator is bad. It is hunting for position, and cant find the coorrect position, so the controller continues to send motor ON signal. Try tapping on the actuator, or unplug it, then plug back in.

[bendysart]

Aloha, well the car returned and the clicking had majically disappeared on the road.. no difference in the environment other than no interior trim.. So the 2nd row seat belt is in and the trim is still in the living room, waiting for a return of the failure.. I really really dislike intermittents..

A NEW problem.. while replacing the power steering unit I have progressed to the place where one is instructed to remove the bolt holding the power steering hose assembly. Several hours of effort succeeded in establishing that the bolt is 5/16" but it's almost impossible for me to get a wrench on it .. when I did it was a small wrench and I was unable to loosen it.. at sundown I got a socket on it with all of my quarter inch drive extensions but I have no idea how to get anything on the other end, it's buried .. This is a trailblazer ext 4wd vehicle with the 4.2L engine and there seems to be no access (probably the engine went in after the steering) .. Going to try to add on more extensions (like 3/8 and 1/2,that I can adapt) this morning.. If there's some proven way I would appreciate it .. going to have the same problem getting it back together..

[Hank]

Which bolt are you reffering to?

[bendysart]

it was the 5/16 bolt that holds the pwr steering supply hoses to the steering gear. A heretofore magic set of extensions finally enabled me to get it off and the steering out.. NEW PROBLEM the replacement steering gear has a different thickness insert for these supply pipes, The original pipes are 3/8 OD the replacement gear accomodates a 7/16 set of pipes.. the supplier says there are only 7/16 holes in the gear that he has on his shelves, do I want to return it ?? NO... so I'm going with hydraulic 1/2"X3/8" o-rings .. wish me luck.. going to do that this morning.. Next step will be to try to find 7/8 pipes for replacement, parts places don't getthat detailed.. Did I mention that GM closed all the dealerships on the Big Island of Hawaii ?? No-one knows where the maintenance dept. guys and their tools are now... Aloha..

[Hank]

Sounds like the the incorrect rack. Never ran into wrong sizes like that. Don't think those O' rings are going to seal.
WOW, no more General Motors Dealers on the big island ?
That is weird. What are customers going to do now?

[bendysart]

All right, steering is a week into reliability testing.. (There is always "upper arm power" steering as a backup). The o-rings are apparently exact right size to be compressed and hold.. they worked on Tuesday the 16th...

Don't know what the other GM owners are doing but I'm not putting power steering replacement in my resume.. there is a rumor that the Toyota dealer is doing repairs, who knows if there are any GM recalls to give them additional irritation (or credence). My best bet is probably to replace the right rear trim and sell it while it's working..

For the record there was another big problem with the gear replacement.. GM installs the Front wheel drive after the gear installation.. it's possible to get a 13/16 socket on the front nuts of the two main mounting bolts.. surprise, the bolt protrudes about 2" beyond the nut and a deep socket is necessary, the Proto Tool truck had one for about $20.. the deep socket barely snaked by the front axle and it is not possible for me and my tools to get any kind of driver on the socket, the axle is about 1/2" away. (I have found (Harbor Freight) what's named as a "Square drive socket Cap" that might have worked, my Proto Tool truck guy never heard of them).. luckily our local chief pilot has a set of tools that included an old 13/16 spark plug socket that slid in and has a hex shape on the top.. an open end wrench worked (EUREKA). Also I found an ancient very rusty one of my own, I returned his.. Incidentally the GM repair manual recommendation to carefully measure the outer tie rod threads and replace them accurately did not obviate the need for realignment...

So much for the record.. the T'Blazer was out of service for about 10 days after the gear was delivered... Don't know what the timeline would have been at the Toyota dealer, specially given the supply pipe size anomaly

Mahalo Hank and Aloha again Ben in Kona