I just ordered 4 of the 2N6284 darlington transistors for
the variable speed blower control used in the Mk3 delanair
system. I’ll have a couple spares, so in case anyone needs
one, I can drop it in the mail for a few $.
The ‘‘special’’ relay also burned out, due to them using a
relay which is NOT air/watertight in a potentially moist
location. I am replacing it with a standard automotive
relay, and I am soldering a 1N4004 diode across it. The
diode is a must to avoid blowing out the climate control.
This is what it looks like inside a relay made for dry
locations, that has been exposed to moisture for 20 years: http://www.myrq.com/IMG_4209s.jpg
Mike–
87 XJ-S V12, vin 135xxx
Evington, VA, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
In reply to a message from Mike B sent Sun 14 Sep 2008:
If you poke around the XJ40 archives you will find a part
number for a sealed automotive relay. That would be perfect
for inside the blower housing.–
The original message included these comments:
The ‘‘special’’ relay also burned out, due to them using a
relay which is NOT air/watertight in a potentially moist
location. I am replacing it with a standard automotive
relay, and I am soldering a 1N4004 diode across it. The
diode is a must to avoid blowing out the climate control.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
3
JaguarJoe wrote:
If you poke around the XJ40 archives you will find a part
number for a sealed automotive relay. That would be perfect
for inside the blower housing.
It’s probably worth noting that most automotive relays are not
sealed. Some even have an obvious vent hole in the bottom. As a
general rule, all such relays are supposed to be installed terminals-
down, so any moisture drains out rather than in.
It’s also worth noting that, sealed or no, some makes of these
deceptively simple electromechanical devices are notoriously
unreliable. I found one particular brand at AutoZone, made in Italy,
that wouldn’t work more than a month or so. And Jaguar reportedly
had so many problems with one brand – Hella, I think – that they
directed dealers to just replace all the relays in the car with Bosch
relays as soon as any problems developed.
In reply to a message from Kirbert sent Sun 14 Sep 2008:
Yep - I have a total of 3 Hella relays here that I’m trying
to find an alternative use for, as they no longer work as
relays. If I can’t find a sealed relay, I’ll coat one
with silicone before putting it in the blower. I’m heading
to Advance Auto to see what they have there.–
The original message included these comments:
It’s probably worth noting that most automotive relays are not
sealed. Some even have an obvious vent hole in the bottom. As a
It’s also worth noting that, sealed or no, some makes of these
deceptively simple electromechanical devices are notoriously
unreliable. I found one particular brand at AutoZone, made in Italy,
that wouldn’t work more than a month or so. And Jaguar reportedly
had so many problems with one brand – Hella, I think – that they
In reply to a message from Mike B sent Sun 14 Sep 2008:
This is a terrible place to put the relays and transistor.
Its cheap to make as a module but a real pain to get to when
they fail. I’m going to have to pull mine again and this
time I’m going to put the transistor and relays somewhere else.
In reply to a message from alex paterson sent Tue 16 Sep 2008:
I wanted to relocate it too, but since they used a
transistor instead of say, something more modern like a fet,
the transistor probably gets pretty hot and probably needs
the airflow, so I am reassembling it with the transistor in
the stock location, as it lasted almost 2 decades. I bought
a sealed relay so I hope that will hold up. Compared to
other projects on this car, this one was a pleasure, but only because a previous owner left out the two top nuts on
the fuse panel! I’m not too sure how I would have gotten to
those if they were in place. For once - Thanks PO!–
The original message included these comments:
This is a terrible place to put the relays and transistor.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
7
alex paterson wrote:
This is a terrible place to put the relays and transistor.
Its cheap to make as a module but a real pain to get to when
they fail. I’m going to have to pull mine again and this
time I’m going to put the transistor and relays somewhere else.
Sounds like a good plan. Remember, though, that inside the blower
housing is a good place for air cooling. Anything that gets warm
will get warmer if relocated to still air.
If I can’t find a sealed relay, I’ll coat one