Jump to content

Heater blower switch. How to test it?


Recommended Posts

Hi. 1995 300 TDI.

Got the instrument panel stripped out to check the heater controls. Fixed the air distribution switch side, but not sure how to tackle the blower switch. I have checked that it has a good ground. I cant read any voltage at the switch at either of the green/white or green/yell wires. Have checked for blown fuses but there are none.

Any thoughts?

Link to post
Share on other sites

http://forums.lr4x4.com/index.php?showtopic=33481&st=0&gopid=323899entry323899

have read of the link above, it's how I reset the heater flap control cables, it should get you sorted.

heater wiring diagram for 300tdi vehicle below

Hi western. I have read your article. It was what made me get on and investigate the heating system. I have also studied and understood the wiring diagram.

This forum is great. (It will be when you mods let me post freely anyhow! ;)

My heater flaps work fine, and all cables work as they should.

The 60 amp fuse in the engine bay checks out fine as does fuse 5 (15 amp) in the cab.

I have traced the green/purple 12v feed to the heaterbox, and it shows 12v with ign on where it enters the heaterbox.

With ign on and the blower switch lever right down the fan does not turn on.

I dont know how to test the blower switch.

Basically, im only getting hot air when im moving at speed. Nothing at stationary.

1/Should i be able to hear the fan come on?

2/If it doesnt come on do i now assume that the blower fan is shagged?

3/Is it a bit of a mission to remove and service the blower fan?

Link to post
Share on other sites

1/Should i be able to hear the fan come on? YES

2/If it doesnt come on do i now assume that the blower fan is shagged? remove the air intake grille & you should be able to reach the fan & turn it by hand, if free to turn, it should be OK, if stiff or not movable, probably a dead motor.

3/Is it a bit of a mission to remove and service the blower fan? a bit of a job, disconnect hoses, remove intake grille & air duct, remove 2 bolts top of heater box to bulkhead [engine bay side], remove mat above passengers footwell,remove 2 bolts & nuts [in engine bay] bottom of heater box,to access motor, drill out the rivets

sounds like the resistor is dead, it lives under the small rectangular rivetted on panel where the wires go in.

(It will be when you mods let me post freely anyhow

sorted now, so your post above is readable straight away as will all subsequent posts. :D

Link to post
Share on other sites

1/Should i be able to hear the fan come on? YES

2/If it doesnt come on do i now assume that the blower fan is shagged? remove the air intake grille & you should be able to reach the fan & turn it by hand, if free to turn, it should be OK, if stiff or not movable, probably a dead motor.

3/Is it a bit of a mission to remove and service the blower fan? a bit of a job, disconnect hoses, remove intake grille & air duct, remove 2 bolts top of heater box to bulkhead [engine bay side], remove mat above passengers footwell,remove 2 bolts & nuts [in engine bay] bottom of heater box,to access motor, drill out the rivets

sounds like the resistor is dead, it lives under the small rectangular rivetted on panel where the wires go in.

sorted now, so your post above is readable straight away as will all subsequent posts. :D

Way hayy...!!

I was reading in the tech articles section about an upgrade using a potentiometer you can buy on ebay. If the motor moves freely would this upgrade, which has a built in resistor, negate the need to strip the blower motor. Could i wire it in without dismantling it do you think?

Thanks for all your help.

Link to post
Share on other sites
  • 2 years later...

disconnect the 2 hoses from the heater, now you have 2 options

1. use a bit of suitable pipe to join them together

2. remove the hoses from cylinder head & fit the 2nd hose [free end] to the cylinder head stub pipe, system will circulate the coolant but have no heater function, I did this when my matrix split a few years ago.

Link to post
Share on other sites
  • 7 years later...

I,m a proper numpty when it comes to auto electrics,

blower switch not working, fan spins freely but it looks like i only get 3v at the lever switch on either of the 2 green wires,

thought it would be easy to change to a 2 speed rotary knob.

any ideas.

thanks

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy