Heater Failure

Discussion and technical advice for 84-89 AW10 & AW11 MR2. 3A-LU, 4A-GE, 4A-GZE.

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goodfella
Posts: 98
Joined: Mon May 09, 2005 4:56 pm
Location: Birmingham

Heater Failure

Post by goodfella »

Hello,

After experiencing no heater fan in the cockpit on number 1 and 2 setting for over 2 years now I bit the bullit and purchased a new heater control unit off ebay to counter the problem. However, after fitting I still have no number 1 or 2 setting???? Number 3 is fine and blows hot air as it did before but I thought the control unit would be to blame for this....any ideas guys?

Both control units cant have the same fault....the odds of this would be crazy? Or am I missing something?

Thanks.
jon_st205
Posts: 618
Joined: Sun Feb 19, 2006 9:37 pm

Re: Heater Failure

Post by jon_st205 »

It's the resistor pack, very common fault. AFAIK it's bolted next to the fan blower (ie. difficult to get to), not inside the control unit itself. Do a seach and no doubt you'll find more info.
jimi
Posts: 2154
Joined: Tue Dec 14, 2004 10:27 am
Location: Kingdom of Fife
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Re: Heater Failure

Post by jimi »

It's a bit awkward to get to. You have to remove the liner for the glovebox, under that you will see the plastic ducting of the heater, the resistor pack is a black unit screwed into the duct looks like this

Image

The one on the left is from a 1a and the one on the right is from a 1b, both interchangeable, but the 1b one is a better unit.
If you remove you are usually able to see if all the wire coils are intact, you can check it with a multi meter on resistance.
resistor pack values between terminals
1-3 = 2.14 ohms (approx)
1-4 = 1.23 ohms (approx)
2-4 = 0.45 ohms (approx)
Terminal numbers are looking at the resistor pack socket
top left = 1
top right = 2
bottom left = 3
bottom right = 4
They are not usually repairable, best bet is to get a replacement unit, the 1b one is much more reliable.

Image

resistor pack is 87138 on the above diagram
goodfella
Posts: 98
Joined: Mon May 09, 2005 4:56 pm
Location: Birmingham

Re: Heater Failure

Post by goodfella »

Brilliant, thanks alot guys!!!
oukie
IMOC Organiser
Posts: 2474
Joined: Thu Sep 28, 2006 7:34 pm
Location: Fife

Re: Heater Failure

Post by oukie »

I think I have one of those spare, in really good condition, I will PM you.
Mk1b White T-bar SC 1987, Mk1b White coupe Jan90, Mk1b White coupe Jan90 (spares), Mk1b Mica blue T-bar Mar90, Mk1b Mica blue T-bar,full climate control,Jan90, 5 mk1's :)
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