Heater Resistor Repair

[Danh001]

Ever since I bought my 2000 Z3, only the max setting (4) of my heater actually worked. It was fairly easy to find that it was a problem with the blower resistor, of which I confirmed a few months ago. I had been neglecting replacing it ever since as they are going for around £70 on Ebay at the moment.

janijoeli over on zroadster.net has a great how to guide on repairing the heater resistor to avoid paying this crazy cost (https://www.zroadster.net/forum/viewtopic.php?t=38741) however unfortunately, my safety switch is corroded beyond what can be repaired using janijoeli's guide.

Of course to fix this I could simply short the switch terminals but I would loose the safety part of the safety switch. Instead, my idea is to solder a new bi-metal temperature switch across the switch terminals like this one https://www.ebay.co.uk/itm/274479686067?var=574636771799 in hopes of fixing the resistor assembly.

I was wondering if anyone has tried this and potentially what cut-off temperature would be ideal for the bi-metal switch? I have gone with 40degreeC cut-off.
Tomorrow I will pull the resistor to get some pictures.

(Image from janijoeli's guide to highlight the switch in question)

 

[Danh001]

Update on this:

I think the problem is a bit niche so I went ahead and tried it anyway and had some success, let me explain...

I first removed the resistor assembly to get a picture of the corroded switch, I then simply used a pair of snips to take off the old switch and cleaned the copper contacts ready for soldering using some light abrasive and contact cleaner.

I simply soldered the new, more modern, bi-metal switch between the two contacts and glued it down under the resistor assembly.

To test, I put the the part back in and et voila, all blower settings now work. I also blew a heatgun into the blower for 30 seconds or so and confirmed that it would break the circuit, I then waited another minute or so for it to cool back down below the 40 degree cut-off and it worked perfectly!

Although the soldering it less than ideal I will probably leave it this way for for now and give any updates over time once I have driven it around for some time. Overall it has been a big success and and great alternative to the £70 price tag of a new resistor assembly

 

[Mint]

Good man for posting folowing on from your repair. Great to see your solution.