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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
Currently if I turn on the aircon, it works only so-so. It’s still warm in the car, but not boiling hot anymore. Also I’ve noticed that only blowers under the front window and the ones aimed at the feet work.
My plan is to first get all the fans to work, see if it gets any cooler, and then focus on the aircon itself.
It is a right hand drive
Where to begin to diagnose why there is no air coming through the vents?
There's only one blower. The vent control **** moves flaps that direct the air from the blower to the floor, dash vents, defrost. If the air conditioning system is working properly it'll cool the cab no matter which direction the air is flowing, tho most people like it to blow from the dash vents so they can feel the air. I don't know the control system well enough to give a step by step diagnosis, but I'm sure someone does and will be along shortly to help.
Blowmotor is fine. I see a panel on the passenger side (see picture). If I open that with my fingers, I can see the blowmotor turn, and if I fully open it, I can feel air coming through that part. So it looks like the control for that “door” is not properly working.
And it also cannot be the blow motor resistor, right? Because I figure that then the blow motor would not run at all.
Here's a schematic of your Heating and Airconditioning system.
That door you reference is the Recirc air door. When Max AC is selected the door opens to bring in (recirculate) cabin air. When the system is turned OFF the door opens as well. In all other selections, the door will close off cabin air and all air is brought in from the outside.
That's the charcoal canister, emissions device. The recirculation door is vacuum operated like the others so the engine has to be on to test. If it's not working you may just have a lack of vacuum. On LHD it enters the firewall on the right side, your's may be opposite.
Study that schematic I posted and the vacuum system schematic, Cruiser posted, for the engine compartment.
The heating and AC system requires vacuum to operate all the door actuators in the HVAC Unit. Each is controlled by the climate control panel (schematic).
The RH drive will be slightly different, and the '96 makes it more different.
Improvise.
The vacuum originates at the intake manifold.
Originally Posted by MightyMauz
The recirc door never opens, no matter which setting on the control unit.
And about the vacuum lines, what do the vacuum lines do, with respect to cooling? Do they operate doors?
I am trying to locate the vacuum circuit but I'm afraid my RHD has a different layout.
You'll have to remove the TB air filter adaptor to see the vacuum taps at the intake manifold.
I can see the tee fitting for the HVAC tap-off and the tube going to the cruise control servo.
Everything else is hidden.
You need to find the vacuum tap at the intake manifold and follow the tube along the firewall to the cruise control servo, then behind the battery down to the vacuum reservoir behind the right fron bumper end cap.
I fixed the vacuum and all vents are working again! It makes a big difference having the air aimed at you instead of trying to cool down the whole cabin!
It turned out that the vacuum hose on the engine block came off and that there was a hole in the hose near the charcoal filter.