Is it possible to backdate heater controls in car?
 

I have an 87 930 where some of the heater control wires have gone MIA and the PO glued down the carpets :(
I have no idea if the heater control even works as I belive I only have the thermostat wires lead to the box - 2 of 2 pin plugs.
There are 2 other plugs which are missing wires being supplied to them.
Should I persevere with running new electrical supply wires and who knows what the wires are/ and do? or can I backdate the controls to a simple lever as on my 911T

I swear the older cars are so simple with wind up windows and lever controls
K.I.S.S. principle 'Keep It Simple Stupid'

regards Ben

Here are some pics to illustrate the plugs/wires I have and are missing:

http://forums.pelicanparts.com/uploa...1295210309.jpg
These are the plugs for which I am missing supply- power?

http://forums.pelicanparts.com/uploa...1295210352.jpg
These are the 2 of 2 pin plugs which I have cables for - but of course have no idea if work as I have no power- or the heater box does have power and is knackered!

Is there a way of jury rigging this heater box or failing that backdating the system to levers?

Thanks to any advice
Ben

Either option is a possiblity. There really aren't all that many inputs to the controller, so fixing the wiring shouldn't be that hard. You could also remove the system and return to levers, if you buy the right parts. I've done it.

JR

My 82 has a control box with a single heater lever sticking out the front of it. I guess it was one of those transition years and the engineers were hesitant in removing the lever.

The auto heat just didn't work for me. Made several attempts to get it going. Finally gave up and ended up disconnecting the heater lever from the control box.

Now it is manual heat with the stock look auto heat controls, etc still in place. Works for me.

4 pin connector:
1 .5mm black/violet
2 .5mm brown
3 (2) .5mm black/violet
4 1.5mm black

6 pin connector:
1 .5mm black/blue
2 (2) .5mm brown
3 .75mm black and 1.5mm black
4 not used
5 1.5mm white/black
6 1.5mm white/green

Of the two 2-pin connectors, one sends a pair of wires to the fan motor for the inside temperature sensor. They are:
.5mm blue/white
.5mm blue

The other two wires are for the temperature sensor itself. I don't know the color for sure. They used to be either white, or yellow. I don't know if they changed on the later cars. You can work backwards from the sensor for that one.

JR

The earlier and later systems have a few differences. The later systems are more complex and don't have the single lever. It's purpose was to allow you to have heat if the controller failed. Some disassembly and fiddling was required.

JR

Thanks JR you seem to have a take on these systems

What do the respective colour wires in the 4 and 6 pin connectors do?

If I can find where these wires have been cut or terminated it may help to know where they came from or what they do.
Is there a simple way to see if the controller box has life?

My mechanic from the UK basically took a piece of flat bar and drilled couple of holes in it for the lever end to slot into and it was jammed up against the gear lever base to jam the lever back and open the heat vent!
It got me from the UK to S France, but I was hoping to either get the heater box working, or failing that start again with levers
Thanks
Ben

4 pin connector:
1 .5mm black/violet - to pin 3 on same connector
2 .5mm brown - to pin 2 on 6-pin connector
3 (2) .5mm black/violet - to fuse 5 in fusebox 1, (other from pin 1, this connector)
4 1.5mm black - to pin 2 on 6-pin connector


6 pin connector:
1 .5mm black/blue - through a bunch of connectors to terminal 58a, light switch
2 (2) .5mm brown - from pin 2 of 4 pin connector, and to ground point in engine compartment
3 .75mm black and 1.5mm black - from pin 4 of 4 pin connector, and to a connector that goes to both the resistor and additional fan relay
4 not used
5 1.5mm white/black - to the resistor
6 1.5mm white/green - to the additional fan relay

These carpets were lightly glued down from the factory. I'd carefully pull them up enough to see if the wiring was still there somewhere. I'd look the length of the tunnel and pull up the floor boards in the front and look there. I can't imagine somebody just clipped all the wires.

JR

Thanks JR
I will endeavour to get the carpet up - unfortunately someone has re trimmed the car and 'well glued' the carpets!
I will try and get her up and running before going the backdate route.
Thanks for the advice
Ben