Screeching heater fan!

Steve C · Post by **Steve C** » Sun Dec 18, 2005 17:33

I think the remaining life of my heater fan can be counted in minutes - it is emitting a very loud screeching noise, as if it is about to seize up and blow a fuse.

Has anybody ever changed one of these? Did Lotus build the car around it? ie. Is it a full dash out job? Is this how she thanks me for filling her up with around 6 litres of Mobil 1???

My car is a 1990 car with AC.

Peter · Post by **Peter** » Mon Dec 19, 2005 19:29

The diagrams i have seem to indicate the blower unit is positioned on the left hand side under/behind the glovebox (in the footwell)
There must be some kind of access on the left side footwell i'd be amazed if you had to remove the whole dash.
But then knowing lotus.....

Peter · Post by **Peter** » Mon Dec 19, 2005 19:30

The diagrams i have seem to indicate the blower unit is positioned on the left hand side under/behind the glovebox (in the footwell)
There must be some kind of access on the left side footwell i'd be amazed if you had to remove the whole dash.
But then knowing lotus.....

bear · Post by **bear** » Mon Dec 19, 2005 21:00

The fan motor is held in with 3 m6 nuts up in the passenger footwell behind the dash ,you can remove it with the dash in place but you will need a socket and an extension bar and then remove the fan motor and impelor.
The one in my car also screached and the brass bushing had siezed onto the motor shaft and was turning in the mounting so after a lot of wd40 and a coating of light grease on the motor shaft the problem was solved and it has been okay for the last two years .
total time allow 1-2 hours and a few lost knuckles
hope this helps K

robertverhey · Post by **robertverhey** » Mon Dec 19, 2005 21:29

And don't forget, ther is an access panel at the back of the glove box, four screws and the whole back panel of the glove box comes out, might improve access

Robert

Steve C · Post by **Steve C** » Tue Dec 20, 2005 02:05

Thanks for the hints .. I've had a quick look and it seems that the unit in my car (1990 SE with AC) is identical to a Mk 3 Supra (86-92) ...

New replacements are only around $60 in the US and I'm visiting in january so may pick one up on holiday! Failing that, a Mk3 Supra must be pretty easy to find in a scrapyard.

The siezed bush sounds very much like my problem!

Steve C · Post by **Steve C** » Wed Dec 21, 2005 17:04

bear wrote: The one in my car also screached and the brass bushing had siezed onto the motor shaft and was turning in the mounting so after a lot of wd40 and a coating of light grease on the motor shaft the problem was solved and it has been okay for the last two years .
total time allow 1-2 hours and a few lost knuckles
hope this helps K

Yep, just fixed it, the lower bush was seized to the motor shaft ... I freed it up, cleaned everything and oiled the bush and absorbant pad with Mobil 1. It runs nice and smoothly now, except that the lowest fan speed still doesn't work ... I imagine the resistor block has a problem - a common problem with the donor Supras!

I need to evolve another joint between wrist and elbow!

Steve C · Post by **Steve C** » Thu Dec 22, 2005 01:13

Anyone know where the resistor block is for the heater blower? Neither the workshop manual or parts manual give any hints!

robertverhey · Post by **robertverhey** » Thu Dec 22, 2005 01:16

Yes I'd like to know where this is too. My fan only operates at two speeds, low and hang on to your hat. All intermediate positions are low speed as well

Steve C · Post by **Steve C** » Thu Dec 22, 2005 01:32

My Supra owning friend says it is in the inlet trunking on his car - so that the flow of air cools the exposed coils of the resistor pack. I'm hoping that removing the back of the glovebox will gain access but this is pure speculation and would be far too easy to be correct!

Redexcel · Post by **Redexcel** » Thu Dec 22, 2005 15:36

Another possibility is that the switch contacts get dirty. When I tried the fan settings in my car for the first time in over a year, a couple of the speeds did not work. My heart sank as I thought I would have to dismantle half the dashboard to find the problem. More out of desperation than anything else, I started to move the slider through the various positions. I was very surprised and pleased when after a few cycles, all the speeds started to work as normal.

I also found once that a dodgy earth connection on the offside engine mount caused one of the speed settings not to work. Except I didn't realise I had a dodgy earth for several months until it deteriorated to the point when I had engine starting problems. Fixing the starting also fixed the heater fan speeds, much to my surprise.

PS Steve , do you have details of the dim-dip bypass mod?
Thanks

robertverhey · Post by **robertverhey** » Thu Dec 22, 2005 22:03

The Haynes Supra Manual shows this (but on a RHD Supra) on pages 3-8 and 3-9 and yes the resistor is indeed located in the ducting between blower unit and heater core. The part is actually shown in the manual and the numbers on it are 87138-24010.

Excellent, can finally get the heater fan speeds sorted......

tonypoll · Post by **tonypoll** » Fri Dec 23, 2005 12:01

Just curious - Which Haynes Supra manual are you using, or would advise?
I looked on Amazon and they list 5 different haynes manuals for the Supra.

robertverhey · Post by **robertverhey** » Fri Dec 23, 2005 13:43

I got mine on ebay, blue cover, number 92025. Published in 1992, covers all models, however only the Mk 2 info is relevant

Ozzy_UK · Post by **Ozzy_UK** » Mon Jan 09, 2006 16:24

out of curiosity is there a haynes manual for the Excel?
if not where do you guys get your technical manuals from?

and where can i get a copy... being a new owner, have always have haynes manuals for every other car i have owned...

Cheers!

Oz.