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Aircon clutch fuse blown

rvdz
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Aircon clutch fuse blown

Postby rvdz » Sat Jun 29, 2019 3:23 pm

I had my aircon regassed a couple of weeks ago. The car was nice and cold on a long drive, but on the way back it started blowing warm air and I noticed the lightening bolt warning light on the dash.

I checked the fuses and realised the aircon clutch fuse was blown (fuse box 1, top left). I replaced it and within a few minutes of blowing cold air the fuse went again. I tried another fuse and the same thing happened.

I'm going to check the wiring in a bit, but not really sure where to start. Any advice or tips?

Thanks in advance.
Roel

1994 Sovereign 4.0 Auto [698760]

NMV 1E
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Re: Aircon clutch fuse blown

Postby NMV 1E » Sat Jun 29, 2019 6:33 pm

Silly / daft question, but is the air con clutch the only "consumer" on that fuse ...... :?:
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nlcrane
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Re: Aircon clutch fuse blown

Postby nlcrane » Sat Jun 29, 2019 7:00 pm

That fuse A1, right fuse box, 10 Amp feeds three things, namely Driver’s lumbar pump, passenger’s lumbar pump and the air conditioning clutch. I suppose we can forget the two lumbar pumps and concentrate on the clutch. See fig.

Image

Power for the clutch comes from point 51 (fuse box) then through the clutch relay to the clutch, a diode and then the supplementary air valve. I would imagine that the relay is OK, but the other three things need to be tested individually for earth faults.
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leo_denmark
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Re: Aircon clutch fuse blown

Postby leo_denmark » Sun Jun 30, 2019 7:22 am

On my 3.2 1992 the electric aux fan is on same fuse as the A/C
The fan was seized, and as a result the fuse blew when driving slowly in hot weather. The fan kicks in quite rarely, so it took some time before I found out the relation.
After fitting a new fan the A/C fuse has not not blown again
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nlcrane
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Re: Aircon clutch fuse blown

Postby nlcrane » Sun Jun 30, 2019 10:59 am

That fuse A1, right fuse box, 10 Amp on a MY 94 feeds three things, namely Driver’s lumbar pump, passenger’s lumbar pump and the air conditioning clutch.

Image
ImageImageImage
1994 Sovereign Gold 4.0

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rvdz
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Re: Aircon clutch fuse blown

Postby rvdz » Sun Jun 30, 2019 12:41 pm

Yes, I have checked, it's the lumbar pumps and the aircon clutch on that fuse, nothing else. The fuse definitely goes about 5 minutes or so after the aircon kicks in so I'm sure that's the cause.

I have had a look and can see a wire that runs from the front of the engine, just by the cam cover through a green plug and down to the aircon pump. That wire has about 14 volts running through it.

However, I cant find the other parts that are in Norman's wiring diagram. Anyone know where they would be on the car, and how to test them?
Roel

1994 Sovereign 4.0 Auto [698760]

rvdz
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Re: Aircon clutch fuse blown

Postby rvdz » Sun Jun 30, 2019 6:21 pm

I had another look this afternoon, and think it's fixed!

According to the Haynes manual all six relays by the bulkhead in the engine bay needed to be light blue, but for some reason the one for the aircon clutch was a different colour.

Having swapped it for a known working one I can hear it click when I turn the aircon on and on a 20-or-so mile test drive the fuse didn't blow. Last time it went within a few minutes.

Perhaps someone nabbed that relay for something else at some point, thinking the aircon wasn't working anyway?
Roel

1994 Sovereign 4.0 Auto [698760]

nlcrane
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Re: Aircon clutch fuse blown

Postby nlcrane » Sun Jun 30, 2019 9:44 pm

Ik weet dat ik het relais genegeerd had, sorry. Ik heb vorige eigenaars niet bijgerekende. Welke kleur was het, of beter nog, wat partnummer was het.
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naki_k
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Re: Aircon clutch fuse blown

Postby naki_k » Sun Jun 30, 2019 11:12 pm

Nice easy fix then for a change.
I was going to suggest replace the relay/ check the base/ check wiring for a short, but now you do not need to.
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rvdz
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Re: Aircon clutch fuse blown

Postby rvdz » Mon Jul 01, 2019 8:43 am

The old -incorrect- relay was dark blue. I don't have the part number to hand but will find it when I get home.
Thanks for your help!
Roel

1994 Sovereign 4.0 Auto [698760]