[xj] auxiliary fan troubleshooting

Check for:
* A stuck, or sticking radiator cooling fan thermostat (in radiator)
* Contacts in the radiator cooling fan relay burnt / welded together
* Shorted diode, in the red diode pack, for the radiator cooling fan .

There’s not too much to this system aside from the duality of power supply.
but when the key is on, the power comes from a switched source, when the key is
off,
it gets power from the battery. Diodes do the switching of power, following one
path
for key on, another for key off, using the relay to actually select which path
to use.
The “on / off switch” , for the Aux fan, is the radiator cooling fan
thermostat.

– Charlie Lumps Admin.
– Customized 83 XJ6 /350/700R4/
– 1986 Jaguar XJ6

turned my car off…sure enough the auxiliary fan was on in full force.
My radiator fan is working as good as ever and I am not overheating.
How do I fix this problem Regards, Michael 85 xj6 VDP

//list policy dictates that messages be trimmedFrom: “Michael O’Donnell” 4michael@concentric.net

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Hi Charlie,
Where is the *radiator cooling fan thermostat in the radiator? * Also I
don’t have the red diode pack , or at least I don’t see one near the
radiator or anywhere for that matter.
Is it hidden somewhere. I thought it would be near the top of the radiator,
but I don’t have one.
Michael----- Original Message -----
From: “Charlie” chache@thethinker.com
To: “XJ List” xj@jag-lovers.org
Sent: Tuesday, April 09, 2002 10:33 PM
Subject: [xj] auxiliary fan troubleshooting.

Check for:
* A stuck, or sticking radiator cooling fan thermostat (in
radiator)
* Contacts in the radiator cooling fan relay burnt / welded
together
* Shorted diode, in the red diode pack, for the radiator cooling
fan .

There’s not too much to this system aside from the duality of power
supply.
but when the key is on, the power comes from a switched source, when the
key is
off,
it gets power from the battery. Diodes do the switching of power,
following one
path
for key on, another for key off, using the relay to actually select which
path
to use.
The “on / off switch” , for the Aux fan, is the radiator cooling fan
thermostat.

– Charlie Lumps Admin.
– Customized 83 XJ6 /350/700R4/
– 1986 Jaguar XJ6

From: “Michael O’Donnell” <@Michael_O_Donnell>

turned my car off…sure enough the auxiliary fan was on in full force.
My radiator fan is working as good as ever and I am not overheating.
How do I fix this problem Regards, Michael 85 xj6 VDP

//list policy dictates that messages be trimmed

The archives and FAQ will answer many queries on the XJ series…
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Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to
Jag-lovers Forums - Jag-lovers.

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Michael O’Donnell wrote:

Hi Charlie,
Where is the *radiator cooling fan thermostat in the radiator? * Also I
don’t have the red diode pack , or at least I don’t see one near the
radiator or anywhere for that matter.
Is it hidden somewhere. I thought it would be near the top of the radiator,
but I don’t have one.

Hi Michael,

The link below shows the red aux fan relay clearly. It is attached to
the radiator support rail just to the left of the fan blade cowling.

http://www.jag-lovers.org/newbies/siii_engine/left_before.htm

Hope this helps.

Jim

//list policy dictates that messages be trimmed===================================================
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There is a large-ish switch, two wires, on the right hand radiator tank,
towards the bottom. The square-ish red diode pack, firewall mounted, is for
the fuel pump circuit. The red cooling fan relay is on the radiator
upper mounting panel, left of the rad.

Doug Dwyer
Longview, Washington USA

Hi Charlie,
Where is the *radiator cooling fan thermostat in the radiator? * Also I
don’t have the red diode pack , or at least I don’t see one near the
radiator or anywhere for that matter.
Is it hidden somewhere. I thought it would be near the top of the
radiator,
but I don’t have one.

//list policy dictates that messages be trimmed----- Original Message -----
From: “Michael O’Donnell” 4michael@concentric.net

The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

Wow, my car is missing that Funny, just the other day I was wondering what
was supposed to be attatched to that mount. I just figured that it was a
leftover for some part that wasn’t on the 1987 cars. My Aux Fan worked last
summer. Maybe my diode just fell off and is dangling, I’ll look in the
morning.

Adam Merkley
1987 XJ6 Federal
Crimson Metallic / Biscuit
Salt Lake City, UT----- Original Message -----
From: “MillTek” mill.tek@verizon.net
To: “Michael O’Donnell” 4michael@concentric.net
Cc: “XJ List” xj@jag-lovers.org
Sent: Tuesday, April 09, 2002 10:19 PM
Subject: Re: [xj] auxiliary fan troubleshooting.

Michael O’Donnell wrote:

Hi Charlie,
Where is the *radiator cooling fan thermostat in the radiator? * Also I
don’t have the red diode pack , or at least I don’t see one near the
radiator or anywhere for that matter.
Is it hidden somewhere. I thought it would be near the top of the
radiator,
but I don’t have one.

Hi Michael,

The link below shows the red aux fan relay clearly. It is attached to
the radiator support rail just to the left of the fan blade cowling.

http://www.jag-lovers.org/newbies/siii_engine/left_before.htm

Hope this helps.

Jim

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The archives and FAQ will answer many queries on the XJ series…
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//list policy dictates that messages be trimmed

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Mea Culpa!

    * Contacts in the radiator cooling fan relay burnt / welded together
    * Shorted diode,  in the red diode pack,  for the radiator cooling fan .

    Should have read

    * Contacts in the **red  radiator cooling fan relay**,  burnt / welded

together
* Shorted diode, in the diode pack, for the radiator cooling fan .

Diode pack, in wrapped in the harness… you’ll have to feel for it.
It’ll be a bulge in the harness, going to the thermostat / cooling fan relay .

Or… check the reverse bias from cooling fan relay terminal 30/51,
to the thermostat for battery supply diode.

Just in case :
(it’s the horn relay, terminal 61 to the thermostat for
the other, switched power is supplied by fuse # 11.

– Charlie Lumps Admin.
– Customized 83 XJ6 /350/700R4/
– 1986 Jaguar XJ6

don’t have the red diode pack ,

//list policy dictates that messages be trimmedFrom: “Michael O’Donnell” 4michael@concentric.net

The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

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