• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
Tips
Tips

TR2/3/3A TR3a dimmer switch question

Share this page

P

powerwagontim

Member
Offline
Hi All,
Havent gotten back to assembling the scuttle vent yet, but to those who offered advice, thanks again. I did fire the old girl up this weekend, first time in about 20 years! Wowser.
Anyway, my question tonight is relating to the dimmer switch. I have the post 60K model, where the dimmer switch mounts in the little box. My question is how does the wiring harness get routhed? I know ihow it goes on the firewall, but does it come up from below the switch, or over the top of the switch box? It really seems like the mounting box needs a hole with a grommit to allow the wires to come in through the back. They would be well out of the way then. Anyone done that before?
Thanks,
Tim
 
My TR3A is pre 60K so I have the other dipper switch, but since you do not seem to be getting any replies, here's a pic from a TR4 that may or may not be similar to how it is done in a post 60K TR3A:

Dipper.JPG
 
Hi George,
Thanks for the pic. The post 60K TR3 switch mounting bracket is almost like a 3 sided box, whereas the TR4 bracket you show the switch mounts on a flat face. The TR# box would have the wires come in over the top (or bottom) and then head to the back of the box, and then connect to the switch. Seems really awkward to me.
Thanks again for the pic.
Tim
 
Tim,
I have crawled, in the dark, into the depths of my footwell to take the following pictures for you. Sorry that they are not the best, but I couldn't see what I was doing!!
The switch appears to be mounted through the box from the bulkhead side. The wires just go from the back of the switch and loop down and then up the bulkhead.
Hope this helps.
Nick
IMG_0219.jpg
.
 
IMG_0226.jpg
 
Nick -- That looks like the switch on my pre-60K TR3A, except the 'box' on mine is fitted the other way 'round.

Don't those angled bits make it hard to depress the switch?

Can someone tell me which orientation is correct?
 
My car is TS64566L and I am surprised to see that it has screw connectors and not spades. From what I can remember my previous TR3 had the same switch, so maybe it changed later in production.
Now that is an interesting idea about the bracket being fitted the wrong way around. I have never seen it before today (!) but when I saw the pictures I did think it looked strange. Certainly not had any problems with it and I am able to rest my foot on the bracket when I am driving without putting pressure on the switch.
Where is Don Elliott when we need him?!!!
 
Hi Tim - here's what I find up in that corner. Hope this is helpful, tho' I'll always yield to Nick, Geo and Don. We're always ready to crawl around upside down in the dark for other TR3 owners!

Tom
 
Nick's photo is definitely the early switch (tho I don't know for certain when the change point was, might have been some later cars got the early switch); and the bracket is backside front.

Not that it matters, if it works for him. Probably does make a better place to rest your left foot ... I've been known to accidentally flash the high beams when squirming around on a long drive.
 
"I have crawled, in the dark, into the depths of my footwell to take the following pictures for you."

Nick: Such a gentleman and a brave soul to look down yonder where the sun dont shine!!!

Tell me. Were these dip switches supplied by Lucas? If not, perhaps the push-on type connectors were not commonly used by other suppliers.
 
Well my car was titled and the VIN# showed to be a pre-60k, but I know the car was altered when last restored. Here's 2 pictures, one showing the orientation of the wiring when I got the car, the other showing that the bracket and switch are different from the other photos above. Mine is the screw-type, but the holes on the bracket are different. I don't know what the other hole in the box face is for. The switch box was mounted the other way around from the earlier picture (with the switch entering the box from the other side). Maybe someone with shorter legs rotated that other box, since the holes are not centered?
 
angelfj said:
Tell me. Were these dip switches supplied by Lucas?
Click to expand...
I see pictures of both of them in my 1961 Lucas catalog, so my guess is that they were supplied by Lucas.

Another conundrum : the detail page in the factory SPC (4th Ed) gives the P/N as 48358, but the numerical index in the same book only has 48359. Must be a misprint, but which is correct ?

Hmm, suddenly BCF won't let me attach 2 photos. Wonder why ? They're tiny little files ...
 
TR3driver said:
angelfj said:
Tell me. Were these dip switches supplied by Lucas?
Click to expand...
I see pictures of both of them in my 1961 Lucas catalog, so my guess is that they were supplied by Lucas.

Another conundrum : the detail page in the factory SPC (4th Ed) gives the P/N as 48358, but the numerical index in the same book only has 48359. Must be a misprint, but which is correct ?
Click to expand...

Your pic shows 31284 -perhaps thats the Lucas number?

The back of the footswitch has "LUCAS" 'standing proud' of the housing (pic attached). All this got me to look in my box of 'original' equipment, and I checked both switches. One I got off ebay and it was painted, so I had to strip the paint off the front to see what was stamped in it. The 'original' wasn't painted and all the characters are readable (tho not very photogenic). The date portion cannot be read off the ebay one, but the 'original' says "31284D 6 58" -and I'm going to assume it is the 2nd 'original' part I've found on this TR3. (The other is the sttering cam, marked "10 58".)

Don't know if any of this is of any interest to anyone, but it's interesting to me to find evidence of originality. My car has hidden it's age well.
 
Remember that Nick's TR3A is RHD. Yours is inside out Nick. You can see mine down behind the steering wheel. The first photo above is the same as a late TR3A but mine is an early dimmer switch. I had to change it last summer after 49 years with the original one.
 

Attachments

  • 10754.jpg
    10754.jpg
    61.5 KB · Views: 351
Wot... no warranty...?? :rolleyes: you do know Lucas had three settings on 'em ,dim flicker and off...
 
I don't know. I reveal all the intimate little areas of my TR to the whole world and then I'm told that my choke linkage is on the wrong side of the carburettor and now I discover that my dimmer bracket is inside-out!! Whatever next! However, I am sure that it is left hand drive. I noticed that on the few occasions when I jumped into the right hand side after I filled up with petrol. It's a bit embarrassing getting out and back into the other side, especially when there is a queue behind the car!
Looking at my first picture of the dimmer switch bracket - are the mounting holes diagonally opposite? If not I can't see how I can mount it the other way around.
 
TexasKnucklehead said:
Your pic shows 31284 -perhaps thats the Lucas number?
Click to expand...
Yup, that's just what it is.

Oddly enough, I found another Lucas document that gives Lucas 132464 for Stanpart 48358. Not sure what that's about.

Here's the other style of switch :
 
TR3driver said:
Oddly enough, I found another Lucas document that gives Lucas 132464 for Stanpart 48358. Not sure what that's about.
Click to expand...
Ok, according to this Lucas catalog (1957 Standard & Triumph cars, Advance Information), Lucas 132464 is a "Screw, terminal" for a 31284A Dipper switch. So the entry in the "Triumph/Lucas Part-Number Conversion List" must be another typo.
 
This is the dimmer switch that we took off TS 81551 L when we started its restoration and we put the same one back on.
 

Attachments

  • 10772.jpg
    10772.jpg
    40.1 KB · Views: 331
Back
Top