1989 LeSabre HVAC doesnt blow

Just bought a 1989 LeSabre.. When I first started messing with it the airflow didn't change. I fooled around with checking connections and found what appears to be a controller of some sort on the right hand side under dash. There is vacuum in one connection and it goes to a pink hose. Now when I change selections the airflow moves but is very weak. The fan runs on high but almost no air output. I read how the evaporator could plug up so removed the fan controller, the evaporator didn't appear plugged but hosed the evaporator down with cleaner and hosed it out anyway. The drain is open but can't handle the volume of a garden hose. So wondering where to go next. If the controller or whatever it is if its weak can it not open doors and the like restricting airflow. Stumped on this one, Any ideas? Thanks In advance
Mark

90% of the time, it is your vacuum supply that is bad, plastic lines crack, rubber line deteriate, crumble, etc. Test by pulling out line at vacuum reservoir- on firewall behind engine, is there good intake vacuum there? Keep going- to all other lines you can trace- don't worry about line leading into dash area- I've never seen it go bad-- it is inside conduit. Use a vacuum guage if needed, 15 inHg is needed to move vacuum actuators-- check cruise control vacuum line for leaks as well.....been there seen that....

Is your system automatic temp control? have a digital temp display?

If vacuum is inadequate, all air is diverted to defroster-- is this where your air is currently flowing to? this is for safety, so if you loose your vacuum supply, you can at least see out if it is rainy.....

Cruise works perfect. There is almost no airflow anywhere. It's the auto-temp with the digital display.

gotta be plugged evaorator-- air has to come out somewhere unless blower motor is running backwards from someone wiring it backwards-- seen that twice...

I agree with bcridd assessment except maybe the plugged evaporator conclusion. When diagnosing a similar problem recently, I measured vacuum at the input to the vacuum solenoid module... That's the module by the glove compartment that you mentioned. (May not be precisely the correct name.) Then I disconnected each vacuum output to bypass the solenoid to test the vacuum motors by verifying air flow out of the correct vents. Then I disconnected the electrical connector and used a multimeter to check the input signals as I changed controls to determine the controller was generating the right signals and the solenoid were responding properly.

I eventually replaced both the controller (used from ebay) and vacuum control module (from dealer).

I also thought my fan wasn't blowing as hard as it should. Years ago I had replaced the fan with one from AutoZone. So I bought an A/C Delco (new). Also replaced the blower module that resides between the ac head unit and fan motor which bolts to firewall (used from ebay). But these changes didn't improve it much if any. I still think it should blow harder but don't know why it doesn't. Maybe there is a problem my air circulation "box" which is a PITA to access or replace.

Good luck.

not gonna play around anymore think gonna go down and tear everything apart. hate throwing parts at it but want it fixed dont want to take to to piddle with it. Looks like to get to evaporator the dash gotta come out so the screw gonna start flyin.
Thanks for the help

Evap on an 89 H car comes out from under the hood...

Thanks just found a procedure for changing the core. The core looks good and I squirted cleaner and hosed it out got shinier. Hard to believe that's the issue. Ive got vacuum to the system and nothing changes think I will call wrecking yard see if they have got a control module

Check ebay

Ok went to salvage yard and got a controller/ module whatever you want to call it. It now changes all airflow wherever it should be but no volume. Checked the fan and motor to be safe and it's ok. Got the evap. core and will start on that tomorrow.
Mark

As far as lack of volume... there may be a blockage due to mice & bringing in debris. You'll definitely find out once you go to install the evaporator. I've encountered that a few times. Those darn things (mice) get in the darndest places!

I hate em they get in everywhere. But when the evap out will know for sure. Regardless after all the work gettin it out the old one wont go back in.:banghead:

Oh wow just noticed exactly how dyslectic I am. The car is a 1998, hokey smokes Bullwinkle there is no dog.

10 years later an H car is a dash pull to swap out an evaporator....just a tad bit of difference

It is a huge PITA to change the evap core. Did it on a grand prix. Avoid if possible imho. Check intake in engine compartment by passenger firewall. The LeSabre have a filter in there that the GPs omit. Make sure it is not blocked. Is there any difference in air flow when in recirc?

If you do change evap core, check all the moving parts on the black box it's housed in. Vacuum motors, linkages, etc. Consider changing that with a good one from salvage. You don't want to have to get to it twice.

After I changed the controller all the air moves like its supposed too. But no flow, has to be the core. Got the stupid rubber cover thingy off and was trying to remove the plate when was called away. Hopefully will get it changed this afternoon.
thanks Mark

I would put it on recirc, remove the resistor block or blower control module(keep connected), and turn the fan on high........if you have a lot of air flow out of the hole, you know there is blockage......

Not sure where the cabin filter is on this vehicle, if it indeed has one.....on the older models I seem to remember it being to the right of the gas pedal....there was a plastic cover you removed.....

OK Here's the update. New evap core and a serviceable controller. The airflow changes as it should. The air conditioner cools but the airflow is better but still low. The fan runs on high and the selection of of recirculate doesn't change much. The door by the drivers foot sticks a little. There has been a new fan motor installed previously could that have been wired backwards? With the recirc door open wouldn't a backwards fan blow in there? The motor has a plug on it would be tough to wire backwards. Just spit-balling.
Mark

My experience is with the Grand Prix. Assuming similar construction, you should be able to unbolt the fan and motor while keeping it electrically collected. Run it and see if it sounds the correct direction. On that squirrel cage fan, it should spin such that the outside edge of each blade leads the inside edge.

Are you checking air flow at the center vents? Those blow more air than the outside vents in my car.

OK Here's an update checked the voltage at blower motor on high and there's about a half volt drop from battery voltage so believe the the fan module is working OK.

Another update. The fan module quit altogether. Got another module out of an 95 Park Avenue at Salvage yard and a used Delco fan motor. Installed the module first. Tha fan ran but no difference in airflow. Put in the used Delco motor and I now have a very nice and cold air conditioner. While the airflow I would not call robust it blows hard enough to be able to easily feel it on your face and at the vents would blow at a natch readily. Probably didn't need to change the evap but after getting it out no way would I put a used one back in. Enjoyed my commute home to nite mid nineties in western Colorado and once on the highway had a nice drive home. Thank you all for your help and hope I can return the favor. While I an not the whiz kid on these newer cars, If you've got fifties fords gimmee a call. Thanks again.
Mark

wow! That's awesome! What a sense of accomplishment you must have too!! Really dig the great & detailed updates. That's what truly makes the forums work! :thumbsup: :thumbsup:

Nice methodical approach. Your updates were clear and thorough. We alkyl benefit from the combined shared experience of the forum.