1997 LC with WIERD A/C and Heat Issue (1 Viewer)

[Knuckle Dragger]

I’m having a very strange issue going on with my ‘97. When I bought this truck a few weeks ago the blower fan wasn’t turning on. Figuring this out was on my “not-so-short list” of to-do’s. Initially I thought this might be a blower motor issue as none of the fan speeds showed signs of life.

Yesterday I was driving down the road and the blower suddenly kicked on in full blast. I had no way to shut it off. Each time I started the vehicle since, it immediately starts up full blast.

Pulled out the AC controller and unplugged both harnesses but the blower persisted.

There is also a strange issue where the actuator on the blower that engages the internal air circulation versus the external air is constantly spinning, opening and closing the block off panel over and over.

The AC controller still has the ability to change the direction of the air. I can switch between defrost, face vents, feet vents. But the buttons for blower speed do nothing and neither does the “auto” button.

I also cannot change the temperature of the air.

Big part of me thinks it’s an issue in the ac controller but wouldn’t the system shut down if the controller was disconnected?

Sort of seems like a grounding issue but I can’t find anything that tells me where the AC system grounds are.

I do have the FSM but it isn’t particularly helpful for my trail mix of issues.

Any advice is appreciated.

 

[baldilocks]

Did the Land Cruiser come with any records or verbal information concerning its history? Maybe it sat for a long period of time and rodents took up residence under the dash. They chew on everything. Urine and feces are very corrosive.

Opening up the dash and perform a detailed visual inspection for rodent damage, corrosion, loose connections, bare wires, charred wires, and any wires added in an incompetent manner by previous owners.

If that checks out, I’d install the hvac controller and run the system while moving any wires you can move by hand and manipulating the controller staying alert to any changes in performance.

If still there are no smoking guns I’d replace the controller before I start digging deeper into the dash unless ripping and 80 series dash apart is your idea of fun.

 

[Knuckle Dragger]

Did the Land Cruiser come with any records or verbal information concerning its history? Maybe it sat for a long period of time and rodents took up residents under the dash. They chew on everything. Urine and feces are very corrosive.

Opening up the dash and performing a detailed visual inspection for rodent damage, corrosion, loose connections, bare wires, charred wires, and any wires added in an incompetent manner by previous owners.

If that checks out, I’d install the hvac controller and run the system while moving any wires you can move by hand and manipulating the controller staying alert to any changes in performance.

If still there are no smoking guns I’d replace the controller before I start digging deeper into the dash unless ripping and 80 series dash apart is your idea of fun.

Thank you for the quick response. I think you are on the right track. I believe the truck sat for a year or so and although I didn’t find evidence of rodents in the interior, I found a mouse nest on top of the fuel rail in the engine compartment.

 

[Knuckle Dragger]

Did the Land Cruiser come with any records or verbal information concerning its history? Maybe it sat for a long period of time and rodents took up residence under the dash. They chew on everything. Urine and feces are very corrosive.

Opening up the dash and perform a detailed visual inspection for rodent damage, corrosion, loose connections, bare wires, charred wires, and any wires added in an incompetent manner by previous owners.

If that checks out, I’d install the hvac controller and run the system while moving any wires you can move by hand and manipulating the controller staying alert to any changes in performance.

If still there are no smoking guns I’d replace the controller before I start digging deeper into the dash unless ripping and 80 series dash apart is your idea of fun.

Rather than tearing up the dash, is it possible to bench test the AC controller? Anyone know what pins should have continuity with corresponding AC controller buttons? Shot in the dark here.

 

[baldilocks]

Rather than tearing up the dash, is it possible to bench test the AC controller? Anyone know what pins should have continuity with corresponding AC controller buttons? Shot in the dark here.

I can’t answer that question nor have I ever read a thread on Mud where someone did such testing. If there is a local clubhouse you could contact through Mud perhaps you could find a loose unit to borrow for trouble shooting.