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Stag Stag AC wiring

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Jedi Hopeful
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I am trying to resurrect the AC on my wife's 72 stag. With the blower switch out of the picture, the AC relay works just as it should. What I can't master is the blower switch.
When I wire it up per the diagram, the AC relay is always on. The ground connection on the switch seems to blow fuses.
Dave
 
Dollars to doughnuts you've got the wrong switch, Dave. There are two different switches that look nearly identical, one for heater-only Stags (as well as many other Triumph applications); and a different one that fits (only) AC-equipped Stags. Even many Stag specialists apparently don't know this fact.

The AC blower switch is Lucas 39257A, Stanpart 151243.
https://www.triumphstag.net/start/technical/partslist/diagrams.php?diag=03-17
The heater blower is Lucas 34477A, Stanpart 131812.

BTW, There are actually several other Lucas switches that also look nearly identical, so check the numbers.

When I went through this a few years back, Michael Coffey had a NOS switch available (at an NOS price). I was able to find a working used one, so he might still have it for sale.

I worked out a way the heater switch could be used, by adding some relays, but don't recall the details offhand.
 
Thanks, Randall
I've spent the afternoon reverse engineering the switch. If it is going to do this, then the contacts must be ABC.
I do have the wrong switch. I'm already thinking of relays and other switches, but nothing on paper yet.
I see you are full up on Stags and 3's.
I'm full up with one of each.
Dave
 
Randall
In the box of stuff that came with the Stag, was a switch. I had to take it apart, but got it to work. I now have the correct switch, and I am pumping 40 degree air out of the vents.
The problem is, with the AC on at road speeds, it sends the engine temp up to 220. Normally, it runs 180.
I have a new Stag radiator from Rimmer (expensive) and electric fan. 180 thermostat. New Condenser with 2 9 inch electric fans.
Ambient, by the way is in the low 90's.
Any suggestions?
Dave
 
Haven't had a chance to fight that on my own yet, Dave, since I didn't get the AC conversion finished before the engine blew a headgasket. But I've heard similar complaints from others, including one of your fellow FL Stag owners.

Make sure the fan shroud is installed (or added if you have an early Stag that didn't originally have it). I believe Glenn Merrill still has the fiberglass repros for sale (originals were steel).

Also check that the Torquatrol is doing it's job (fan should stop in less than 1/2 turn when spun with the engine stopped, and show no play whatsoever); and that the condensor fans are turning the right direction. (Don't laugh, I've seen professionals overlook this point.)

If you have the 72 or 73 intake manifold, make sure you have the proper thermostat with the 'foot' to block off the bypass line. (Some people have reported that the footed thermostat won't work in the early manifolds, but I didn't see a problem with mine.)

Since you've probably done all that already, my next suggestion would be to add a "chin" spoiler to the apron under the front bumper. You can either try fabbing something from plywood, or I've heard the TR6 spoiler can be made to work. If you compare the profile of the Stag to other cars, the Stag's 'chin' is much higher relative to the rest of the car, which I believe allows a high pressure area to form behind the radiator and block, to some extent, air flow at freeway speeds. The spoiler turns that into a low pressure area, which literally sucks air through the radiator at speed.
 
I've got an electric fan on the radiator, and have checked the direction of the condenser fans.
I'll have to look into the spoiler. It's all about airflow.
 
FWIW, I found my Stag actually ran hotter on the freeway with an electric fan mounted as a pusher than with the original fan. Even without an AC condensor mounted.
 
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