Internal fan and rear heater still operating after ignition off and key removed. (1 Viewer)

[myislandcruiser]

Hi, I am new to this forum and, though I am reasonably handy, I am new to vehicle diy in general, so please bear with me.

I have a 1999 Landcruiser Amazon. Right hand drive. Recently it has developed a problem whereby:

1. The fans (i.e. the warm/cold air blowers operated from the AC control unit) continue to operate even after the ignition has been switched on and the key removed. This is also true for the rear heater button on the same central panel (not the power heater, which is on a separate button to the right of the steering column near the driver door).
2. The rear heater can also come on of its own accord. i.e. I park up and it is off, but when I return to the car the rear heater has switched itself off. Obviously my concern is the battery could drain and leave us stuck.

After some reading, I figure this is most likely to do with a faulty relay (perhaps due to the very wet weather we have been having). However, I am cannot figure out what part (or maybe parts) it would be that I would need to check/test/replace. I am not particularly electrically minded, so would prefer a 'swap it and see' approach if I can identify a likely culprit and the part is not too dear. If that seems impractical, then advice on the testing procedure in the most basic terms and with the most basic of tools would be appreciated.

I did also try the fault finding process (press AC and recirc button while switching on ignition). This resulted in the rear defogger button flashing orange (approx 1sec intervals) along with alternate flashing of the selector dial for the front windshield defogger (orange flash) and the speed selector dial for medium (green flash - i.e. one click up from Lo). I don't think I can attach a video, so apologies for this clunky explanation.

Lastly, as a temporary measure to reduce battery drain risk, I have pulled the 10A fuse for the rear heater, which at least has stopped that (the LEDs on the button still light up when it is pressed, but heater doesn't operate). But obviously this doesn't stop the main air at the front from staying on and we need that to be operable in any case for defogging and getting warm.

Lastly, before you suggest that it should go to a mechanic, I would also love to have someone else look at this, but we are based on an island with limited mechanics who have limited time - i.e. it wouldn't get seen for months. Getting to the mainland is tricky. Therefore, if I can isolate and fix the problem it would be a massive relief. As I said, I am handy outside of car maintenance, and I have half a brain that I can apply to the problem. It is experience that I lack. If you have any thoughts, please describe it in basic terms - especially for the locations of the bits I would need to locate. I think some of the relays are outside of the main boxes (?).

Thank you in advance.

 

[sunfic]

it is the internal blower fan keep running? it should be the AC control unit.

 

[myislandcruiser]

Hi @sunfic. Thank you for the response. Yes exactly - the internal blower fan runs even with ignition off. And the rear heater also continues to run (in fact comes on off it's own accord). What do you mean by the AC control unit? Do you mean the actual unit inn the dashboard with the buttons? Or some hidden relay?

 

[sunfic]

Hi @sunfic. Thank you for the response. Yes exactly - the internal blower fan runs even with ignition off. And the rear heater also continues to run (in fact comes on off it's own accord). What do you mean by the AC control unit? Do you mean the actual unit inn the dashboard with the buttons? Or some hidden relay?

you can take picture of your AC control panel. there is a computer behind that and depending on if you have GPS navigation, the computer location is different.

 

[myislandcruiser]

Hi. This is the unit. No GPS/Nav system.