On 8/12/2014, Thomas Aczel wrote:
"One frustration was the under dash heater controls and panel. This came as a kit from NTG in the UK; fascia panel, sliding switch and mounting hardware.
"The arc of the sliding switch does not match the arc of the plastic molded panel on its back (forward, foot well) side, so it would bind completely in the central part of its travel. It also only had enough clearance to pull the fan switch on at each end of the slot (just). In the end the only solution proved to be to weld up the mounting holes on the switch and to re-drill them closer to the switch's edge, taking the switch forward from the panel a couple of millimeters. It then was able to move freely throughout its arc of travel without binding, and still allow clearance for the switch's 'fan on/off' role to function".

On 8/14/2014, Thomas Aczel wrote:
"You'd have hoped however that buying a complete kit that everything would work together wouldn't you? My heater control fascia panel had a small gold oval shaped adhesive label saying 'Made in China' (or Taiwan, I now forget which of the two). The panel itself is plastic, not heavy and thick like Bakelite". -- Tom

Note from Barney:
Not certain yet, but I believe the mechanical lever assembly is correct, and this is a problem with shape of the the plastic panel. It is against my morals to modify a perfectly good part to accommodate a faulty replacement part, but I don't know which part is bad. If the plastic panel is wrong, then the fix should be to grind away the excess material in the back side of the plastic part, but apparently the plastic is too thin to modify in that manner. Otherwise send the part(s) back for refund, and vigorously urge the supplier to fix or replace the parts. If the customer will keep the parts, then the supplier has no incentive to fix it.

On 8/15/2014, Thomas Aczel wrote:
"Unfortunately the fascia panel is relatively thin plastic. It would have been MUCH easier to grind away the back of the panel to gain the needed clearance. There was unfortunately much too little thickness in the panel to allow this. Similarly there was not enough plastic around the bolt holes to allow me to elongate the holes to allow me to move the panel rearward to gain the needed clearance. There seemed no alternative to redoing the switch holes to move the switch forward. This incidentally was not a light graze of the switch onto the back of the panel. The switch dug in hard at the centre of its travel.
"The kit contained the fascia panel, the switch, the bolts and the spacers. The fibre washers were not there. Neither was the ferule needed to secure the heater valve cable. This combined kit is not currently offered, but the individual components, presumably from the same Asian source are still listed by NTG and others. I did try to let NTG know through the "contact us" part of their web site (MG Bits 4 U), but it seemed to be rather difficult to navigate to get my point across. And I don't wish to phone them in the UK from Australia. While I'm big on returning faulty parts, in the end I thought "damn, I can't be bothered", especially since about a year or so had elapsed since I first bought the kit in preparation to ultimately fitting a heater to my MGA". -- Tom

Ten years later the problem is still here. Being persistent we have a little more information and some more pictures. Apparently the mechanical part of the switch is okay, but the plastic panel is wrong. -- Click on the picture at right for lager image, and look where the red arrow is pointing. Notice the vertical offset in the steel control lever. This is where the lever hits the rear side of the control panel in mid stroke (for most of the travel width).
The curve radius on the plastic control panel does not match the swing radius of the switch lever. This results in the switch lever "jog" dragging on the back of the panel in mid stroke. The interference here is so bad that when it jams in place the lever cannot be pulled forward to actuate the switch, so the blower cannot be turned on (except at the extreme left and right ends of the lever travel. That is, you may be able to turn the blower on at full cool and full heat positions only.

Someone had the idea that you might be able to flatten out the control lever (remove the offset bend) and re-form the lever with the offset bend a little farther back. Even if that would work, it is against my morals to modify a perfectly good part to accommodate a faulty replacement part. If you did that, then next time you might need to replace the switch, you have the same problem all over again. The proper solution is to throw away the faulty plastic panel and get a good one that will fit and work properly.

The other suggestion was to grind away some of the back side of the control panel to provide swing clearance, and then grind some more to provide additional clearance for the switch actuation when it is pulled forward. But the new plastic panel is not very thick, so you might grind all the way through the panel before you get it to work.