[W126 Coupe] FW: a/c problems

[Dick Spellman]

Hi Hugh,

Take the two spade lugs going to the r/d pressure switch and jumper them.
These do not operate the aux fan, that would be the fan limit switch you
jumped from what you describe.

The KLIMA is fine from your posting.

If the compressor kicks in with the correct wires jumped on the r/d, please
check your pressures once again to be certain they are within range.  Low
should be 30-45 depending on your air temp near the condenser when testing
and high should be around 160-175.

Report any noise or grumbling with compressor running as this may be a sign
of low PAG 150 oil assuming you are talking about a Nippondenso compressor.

You say pressures were good, I assume these were static pressures you were
reading where the compressor was not active?

In any event, it's either low pressure or the r/d pressure switch is likely
bad.

Last item will be the speed sensor on the compressor but, I'd start with
that r/d pressure switch and circuit first.  You can always try calling me
if that will help.

Regards,
Dick
508-641-8477 east coast



On Tue, Jul 22, 2008 at 7:25 PM, Hugh MacGregor <hugh587 at hotmail.com> wrote:


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> ------------------------------

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> ----- Original Message ----- *From:* Hugh MacGregor<hugh at badrockbikes.com>

> *To:* mb coupes <mbcoupes at mbcoupes.com>

> *Sent:* Tuesday, July 22, 2008 6:56 PM

> *Subject:* a/c problems

>

> *Hi All*

> *My 86 560sec was converted to 134a by the previous owner. Last summer I

> topped up the 134a charge and the a/c worked great. This year I did the same

> thing, high low pressures are in range, still the compressor won't come on.

> I looked back through the archives for tips , I jumped the pressure switch

> on the dryer at the R/H side of the radiator, the auxillary fan came on the

> compressor did'nt. I jumpered the 5&7 pin on the klima relay and yes the

> compressor kicked on. I swapped the klima relay with a good one and still no

> compressor. I see in the archives that Markus Meyer had a similar problem

> last year, I think he installed a new speed sensor on the compressor, but

> I'm not sure how to test it. Can anyone help me out! I'm roasting.*

> **

> *Hugh MacGregor*

> *86 560 sec*

>

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