Photo sensor on 3.2 DID gen 3

[zoobie]

hi all.

the workshop manual talks about testing the "Photo sensor" which is situated on top of the dashboard by covering it with your hand. It says that the fan speed should drop, if not, replace the sensor.

What does this sensor do?..has anybody replaced this?

thanks for all your help..I am learning.

Zoobie

[Mcnoogle]

Hi Zoobie,

Not that I know anything about these things, but sounds to me like its there to tell whether its day or night?

Seems to make sense that the fan would probably be able to run a bit slower at night.

Someone who knows will probably reply soon enough.

Cheers
Ned

[4ePikanini]

it is a light intensity sensor.

the a/c climate control adjusts the cold air/warm air mix based on the amount of sunlight coming.

For example. If the outside temp is 30 celsius and the sun is baking the a/c will have to work very hard whereas, if it's 30 celsius outside but it's dark already the a/c doesn't need to work as hard as you don't "feel" the heat so much and you don't have the radiant heat coming in. Only the ambient heat.

some cellphones uses the same concept to adjust the brightness of the lcd screen.

A very basic example is the day night light switches on security gates. The one in the pajero has a larger range though.

[zoobie]

thanks guys...always helpful as ever.

The workshop manual states that if you cover the Photo sensor with your hand, the fan speed should decrease...mine does nothing.

so off I went to MM this afternoon and tried to buy one....they didn't have a clue what I was talking about, nor could they find it on the parts list.

They are now going to contact head office to find out.

Will keep you posted.

[4ePikanini]

I suspect it may have a delayed trigger otherwise the fan will hunt around a lot if driving in a place where loys of shadows are intermittently cast by trees or buildings etc.

I think a truer test would be a thermometer in the vents and log the temp when the sensor is exposed to sunlight and when it is covered. The fan speed may be the same but the temp may differ.

[CATS]

Also make sure that the settings when testing is that the aircon is on and set to automatic on both the fan speed as well as the position/vent selectors when testing.

CATS

[zoobie]

thanks for all the responses..I am learning fast. Will test it this weekend.

[FICZUS]

Ok Guys, so where is this "G" spot exactly?
I was searching,for it ,nop...
My paj is a 2002 3.2did SWB model.Has she this photo sensor?
Peter

[4ePikanini]

On top of the dash in the middle close to the windscreen. It is in the middle of the defrost vents.

Looks like a big black marble sunk 3/4 way into the dash.