The definitive heater modification

Frequently asked technical questions and common modifications/improvements
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electrokid
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Post by electrokid » Sat Mar 17, 2012 8:16 pm

EJX is the code for Furio red - which is slightly darker than Venetian red. The actual colour of your car should be written in the space provided in the original owner's handbook. There are cars with EJX under the bonnet which may be in Furio or in Venetian - but if you use the wrong one to touch up blemishes the difference will be obvious.
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Grgabx
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Re:

Post by Grgabx » Thu Dec 27, 2012 1:52 pm

jeremy wrote:The circuit board is in the earth return circuit - ie the circuit is through the ignition switch, through the component (ie blower motor etc) through the plug into the circuit board thence to earth.

So you have earthed the control coil of the max speed relay (click) and the blower motor - so that part of the car wiring is OK. Working from the right on the circuit board terminals 2 and 3 are connected together on the board and are earthed - terminal 1 is the panel light.

If none of the 3 functions work (panel lights, max speed and blower motor) then there may be a general board fault but this is unlikely as the whole thing is so simple.

If the panel lights only work then the chances are that there is a problem with the small 'wiper' situated under the rotating disc has been lost or displaced. Its function is to join 2 segments under the rotating part of the switch together and complete the circuit. If this is missing I'd still expect the panel lights to work subject to what I said in my earlier post (namely with good bulbs etc.)

Hello guys after a long time. first of all I wish you Merry Christmas. Second, i quoted this post because I have problem with control panel. I thing I have lost the small "wiper" under the rotating disc. Can anyone tell how does it look(does it have 2 bumps for each circle?) and how can I make it out of copper plate i have.
I also mede modification but haven't try it yet because of this metal plate. And the bulbs drop dead long time ago. I'm thinkong about LED displacement. Is it available somewhere?
Thnx
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mat_fenwick
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Re: The definitive heater modification

Post by mat_fenwick » Thu Dec 27, 2012 2:04 pm

There is a thread on here some about replacing the bulbs with LED drop in replacements, which are readily available from eBay and the like. Depending on which type you go for there are issues with brightness and directionality, and the dimmer control will have little effect.

The contact under the rotating disc can be one of (at least) two types. There is one made from a springy metal strip, with (IIRC) two bumps to make contact with the PCB. The other type I've seen looks a little like two balls joined together. This uses two tiny springs to keep contact with the PCB, which can go missing!

If you're struggling to make something, I have a spare modified PCB which could be available.
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Re: The definitive heater modification

Post by Grgabx » Thu Dec 27, 2012 2:42 pm

thaks for the note. I will first try to make this plate with spring improvisation. Actually i will try to connect this two circles to se if the blower works at all after this modification.If it doesn't work I'll let you know.
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Re: The definitive heater modification

Post by Grgabx » Fri Dec 28, 2012 10:15 am

I've tried with small wire. the speed was increasing but when I jump to last part of circle the blower didn't woork. That part was over connected as described in this posts. I also suspect that only one fan works. I will probably take them out and check and clean. It shouldn't be a problem. A few screws and connectors. Do I have to take out the wiper motor out first?
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mat_fenwick
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Re: The definitive heater modification

Post by mat_fenwick » Fri Dec 28, 2012 11:50 am

Two motors - do you have air conditioning then? If you do you will probably find that there is a switch on the temperature control dial which only enables the full speed relay when set to fully cold. If the contacts in this are dirty you will never get full speed.

You don't have to remove the wiper motor itself but you do have to take off the arm and plastic vented panel beneath it. You should be able to tell if both motors are rotating by ear though.
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Re: The definitive heater modification

Post by Grgabx » Fri Dec 28, 2012 2:03 pm

I do have air condition that is installed after and it contains two buttons installed in konzole nera handbrake. one is for turning ON the air-con and other is closing the air channels in ventilation-recalculating air.
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Re: The definitive heater modification

Post by frommbold » Sun Apr 07, 2013 1:20 pm

(soory my english - its hermann the german writing)
after overhauling and checking my heater system, my conclusions to this mod:

- the increase of ventilation energy by reducing the residual resistance of the transistor is nearly not to realise. the effekt is less than two drops of oil on the bearings of a 20 year old vent motor or its cleaned collector.

- if you realize an major increase of ventilation by this mod, it is not caused by the residual resistance of the transistor. its caused by a switched resistance of the transistor. the reason for this switch is shown here:
http://www.bxclub.co.uk/forum/viewtopic ... 15&t=17847" onclick="window.open(this.href);return false;

-after replacement of the orgiginal element against overload (which contacts were only realized by pressing) by an ptc thermo switch with was solderd to the pcb, there was no difference in power to realise, which may be worth to do this mod.

- so if you realise a bigger difference, check the contacts of the element for overload protection.

nevertheless there is an advantage of this mod: the transistor produces no more heat at full power. in this way the risk of its distruction is reduced strikingly.

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Des Smith
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Re: The definitive heater modification

Post by Des Smith » Fri Mar 13, 2015 7:34 pm

Just to report my fan stopped working, intermittently at first, then permanently. Demisting has therefore been no fun this winter, to the point that I finally had enough and plucked up courage to take the panel off and do the mod. It all went as per the thread instructions, but when I tested it, nothing. I then tried bridging the pins as described and bingo, a veritable gale! So I've soldered a bridge between pins 3 and 4 and re-assembled and normal service has been resumed. In hindsight, a dodgy earth would explain the intermittency.

When I looked at the panel bulbs, they had both blown, so now I just need to get hold of replacements and it will be dead simple to take the panel off and pop them into the holder.

:D :D :D
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David
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Re: The definitive heater modification

Post by David » Fri Mar 13, 2015 11:13 pm

Last time I had the dash out of my car, I traced the wire back that tends to loose the earth. It actually goes back to one of the pins on the heater resistor. It could be corrosion on a pin or inside the resistor that causes all the trouble.
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Des Smith
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Re: The definitive heater modification

Post by Des Smith » Fri Mar 13, 2015 11:34 pm

David wrote:Last time I had the dash out of my car...
Last time? How many times have you had the dash out?! Respect to you! Thanks for the steer, but somehow I think I'll need a very big incentive before I pull out the dash to look for a dodgy earth.
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Re: The definitive heater modification

Post by Defender110 » Fri Mar 13, 2015 11:35 pm

Well done David, I wondered where it went to.
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Re: The definitive heater modification

Post by citronut » Sat Mar 14, 2015 9:41 am

Des Smith wrote: just need to get hold of replacements
try the likes of

http://tinyurl.com/new62w9

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Des Smith
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Re: The definitive heater modification

Post by Des Smith » Sat Mar 14, 2015 11:40 am

Hmm. Bit pricey. Just been down the local motor factors. 20p each, so I bought a few as spares. :D
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Re: The definitive heater modification

Post by Way2go » Sat Mar 14, 2015 11:57 am

Des Smith wrote:Hmm. Bit pricey. Just been down the local motor factors. 20p each, so I bought a few as spares. :D
:? How come? 17p is better than 20p. Still, you managed to buy quickly & fix. :-D
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