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What is the function of this relay?

I've posted a picture of the relay/fuse panel in the engine compartment of my 964.

What is the funtion of the tall black relay. The part number is 811 951 253. Thanks L


Last edited by LCOX; 12-25-2020 at 09:29 AM.. Reason: Reposting picture
Old 12-25-2020, 09:26 AM
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Rear eng compartment relay

If I'm not mistaken that is for the rear auxiliary blower mounted on side of intake ...
Bert
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Old 12-25-2020, 09:35 AM
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Yes, it's the double relay for the rear blower. The other relay being for cars fitted with A/C (M573).
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Old 12-26-2020, 07:46 AM
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It is the same relay used for oil cooler fan and AC condenser fan (both are in fuse box in frunk)

The engine compartment relay is subject to great heat and can fail..I have had to replace that and my oil cooler relay

Good idea to use contact cleaner when refitting these
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Old 12-27-2020, 09:40 AM
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Anyone with knowledge of testing this relay with an ohm meter?
Old 01-13-2021, 09:51 AM
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It's a double coil/contact relay for a two speed blower operation.

Resistance test across first coil at 85 and 86 and second coil at 85c and 86. 86 is common.
Continuity test across 30 and 87.
Continuity test across 30c and 87c.
12VDC power test at 30 and ground and 30c and ground.

What seems to be the issue being resolved?
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Old 01-13-2021, 03:14 PM
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Quote:
Originally Posted by bazar01 View Post
It's a double coil/contact relay for a two speed blower operation.

Resistance test across first coil at 85 and 86 and second coil at 85c and 86. 86 is common.
Continuity test across 30 and 87.
Continuity test across 30c and 87c.
12VDC power test at 30 and ground and 30c and ground.

What seems to be the issue being resolved?
Thanks for the diagram for rely function!!!
Old 01-14-2021, 12:21 AM
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Bazar01. I tested the relay. Results below.

Resistance across 85 and 86. 74 ohms
Resistance across 85c and 86. 71 ohms

12 volts at 30 and 30c sockets at the wiring harness plug

30 and 87 had no reading on the meter when I checked for continuity. The same for 30c and 87.


12volts at socket 30 on the wiring plug
12 volts at socket 30c on the wiring plug
Old 01-14-2021, 08:31 AM
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LCOX, what electrical issue are you having with the relay and engine compartment blower?
Old 01-14-2021, 09:45 AM
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I can hear the relay clicking about 1 or 2 times a minute. The engine is stone COLD and not running. The engine mounted fan is not running at this time. I haven't driven the car and gotten
the engine up to operating temps yet. This may be draining my battery as well. That's the reason i wanted to check out the relay closer.

Car
Old 01-14-2021, 04:14 PM
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Ok. Can you feel the relay click aside from hearing it with the ignition switch off? No key in ignition switch?

Old 01-15-2021, 05:07 AM
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