What Are These Things On My Right Hand Drive 1999 Ls400?

[Mile_High_Flyer]

Not problems, but I'm just wondering about the following on my 1999 right hand drive LS400 from Singapore. Positions of the items may be slightly different on LHD cars, I don't know.

1. On the firewall, there is a unit that looks like a horn, but not a wind tone type. What might that be for? Someone said it was for the car alarm, or panic alarm, but they use the standard wind tone horns hanging from the cross bar in front of the radiator. Nor is it the alarm beep to let you know the car is locked or unlocked. That appears to come from behind the front wing.

2. Also hanging from the same bar, directly behind the left horn, is a box with 4 wires. Inside the box is a little foam air filter, and a small circular unit with a fine mesh. My first thought, before I checked inside, was possibly the outside air temperature sensor, but it isn't that!

3. Where is that air temperature sensor?

4. A small problem I just thought of. Each time the ignition is turned on, the driver's mirror housing moves outwards very slightly. After a number of times, I hit the folding button a couple of times, so the mirror starts folding in, then out again, and it always stops in the correct place. Is there any easy way of correcting this? It would seem unlikely to be an easy fix!

Many thanks, Keith

[SKperformance]

The horn is for the alarm beep on the firewall.

Ambient air temp sensor is behind the rebar.

Clean it .

[steve2006]

Re question 4, other owners have had exactly the same problem and up to now no one has found the cause, sorry.

[1990LS400]

I think the little box behind the left horn is the smog sensor -- my U.S. spec 2000 LS400 has it too. It's the gizmo that allows the HVAC system to automatically switch between outside and recirculated air depending on outside air quality. The sensitivity of the smog sensor can be adjusted using the HVAC buttons on the center stack but I'd have to look in my owners manual for the procedure.

[Mile_High_Flyer]

I think the little box behind the left horn is the smog sensor -- my U.S. spec 2000 LS400 has it too. It's the gizmo that allows the HVAC system to automatically switch between outside and recirculated air depending on outside air quality. The sensitivity of the smog sensor can be adjusted using the HVAC buttons on the center stack but I'd have to look in my owners manual for the procedure.

That seems to make sense, thank you. My manual also has the adjustment procedure. Thank you for your help :)

[Mile_High_Flyer]

Re question 4, other owners have had exactly the same problem and up to now no one has found the cause, sorry.

Thanks. It's not a great problem so I'll just have to accept it as it is. Cheers.

[Mile_High_Flyer]

The horn is for the alarm beep on the firewall.

Ambient air temp sensor is behind the rebar.

Clean it .

After having another look, that horn is actually mounted on the upper, inner fender side, next to the firewall, but not actually on the firewall. On mine, it's not the alarm beep. That sound comes from either inside the lower fender area, or underneath the car. I haven't tried getting underneath to try and find it, as yet. The sound doesn't change when opening the hood, nor when holding the horn. Haven't looked for the air temp sensor behind the bumper, as yet, but will do so soon. Thanks for your help :)