[urq] 4kq/urq AC Re-install

Sat Jan 19 14:11:25 PST 2008

Thanks Tony,
Unfortunatley my Bently is 3,000 miles away from me in a different country,
I have the 5ktq Bently and some diagrams of the underFusebox panel.  Here is
what I know so far.  And this car has 5ktq MC Engine in it.

On the bottom of Fusebox PINS:
* A87M comes from Relay Output 54/87 and should go directly to AC Compressor
to turn on AC compressor and to ISV Relay so computer can compensate.
* A30M is +12V from Fuse to power Relay at Pin 56/30
* A86M ????????
        This is the one that's confusing me.  It goes to the AC Thermostat
but I cant tell from my basic Bently wiring skills if its 12v or Ground.  ON
the Relay it goes to pin 55/86.  What does this wire need to do to have
power.  I'm assuming I run this wire to the Thermostat but then where?  If
I'm reading this correctly then it looks like the AC Thermostat Switch must
be closed for the relay to work.  I'm also assuming that the this wire goes
to the Radiator Fan somehow but I'm not sure where.

*Relay Pin 57/85 is comes from the Switch to activate the relay.

If someone has a spare 5-minutes could they look at a 4kq Bently and tell me
where this PIN 55/86 from AC Relay goes to.  What color wire, etc.  And from
the Thermostat then where does it go?

Thanks

Todd

> From: <tlum at flash.net>
> Date: Wed, 16 Jan 2008 15:11:27 -0800
> To: <tquattroguy at yahoo.com>
> Subject: Re: [urq] 4kq/urq AC Re-install
> 
> Hi Todd,
> 
> Can't answer all your questions but here is what I remember.
> 
> 1.) The evaporator on the 84 and up cars have a low pressure switch mounted on
> them.  The urq did not have low pressure switch.  In fact the compressor would
> turn on with no freon in system.
> 
> 2.) The old style urq lever operated CC mounted the thermostat right on the
> lever mechanism.  The probe ran on a long tube down and into the evaporator.
> 84 and up mounted the thermostat right on the evaporator.
> 
> 3.) The old style mechanism also had a vacuum switch on it that closed the
> recirc flap when in the far left position.  The later cars used a vacuum
> solenoid activated by the AC switch that also turns on the compressor.  You
> can get a big intake vacuum leak if that switch cracks.
> 
> 4.) I could never get the levers to set right, so I dumped them and went with
> the later levers and AC switch.
> 
> As for your fan issues, these should be a easy fix once you've followed the
> wiring diagrams.  4kq's dont have any resistors in the rad fan circuit and the
> rad fan motor is a single speed, so the fan should just turn on continously
> when the AC is on.
> 
> HTH,
> 
> Tony
> '83 urquattro #302
> '87.5 coupe GT Special Build
> 
>  
> 
> = = = Original message = = =
> 
> In one of my younger years, I thought it would be a REALLY good idea to
> remove 80lbs from my 4kq by removing all the AC Components and put a turbo
> 10v in it.
>   NOW, Said 4ktq is in Belize with a Turbo motor so I'm trying to re-install
> the AC system from my UR-Q track car into this 4ktq.
> 
> DISCLAIMER:   I do NOT have my Bently down here so I'm sorry for asking
> wiring questions that I could answer with it in hand.
> 
>   Its all installed and fitted.  Problem is, I cant seem to remember how the
> wiring goes.
>   I have an 84' 4kq so the wiring should be similar to an 85' urq.  I have
> verified that the switch on the ClimateControl Face in the CenterConsole
> does have Continuity to the Relay in Position 11.
> 
> 1) FIRST:   Here is where it gets odd.  It seems that urq AC Evaporator
> under the dash has a Relay attached to a temp sensing wire.  I don't know if
> the 4kq unit had this as I can not find anywhere that it would plug in.
> Does anyone know if the 4kq wiring has this? From looking at my 5ktq Manual
> which I do have here, it seems that would be a thermostat to kill the AC
> Compressor when the temps at the Evaporator drop below 32degrees.  I would
> assume this is mandatory so if it is, and 4kq had it, WHERE then are the
> wires for it.  I can NOT remember.
> 
> Also, currently the fan is not engaging when AC is on.  I'm hoping this is
> simply a matter of needing that Thermostat hooked up.
> 
> 2) Next>....This thermostat has a lever on it.  I believe this is because
> early ur-q's used to turn on the aC when you moved the lever to the far
> left.  Then the 4kq and 85' urq, got a switch to turn it on.  So I would
> assume this lever needs to be in a certain position and taped in place to
> keep it activated.  Anyone know what that position is?  I can probably play
> with it to figure that out.
> 
> 3) LAST QUESTION:
> Can someone tell me:  What color is the wire going to the Compressor and
> what harness it comes out of.
>     IE...does it sprout out of the headlamp harness that runs up the driver
> side and across the front of the car?
> 
> Thanks
> 
> Todd
> 
> 
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