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MG TD TF 1500 - Help with Light Switch

I had to replace the light switch on my 54TF. When I took the old one off there were three wires that were pigtailed together on one terminal and two single wires on the other two terminals. The head lights will work but the tail lights will not. Also the switch becomes very hot to the touch. Does anyone have any info as to what may be going on?
Thanks for any help
Bud W.
S.A. White

Some heat is normal, but excessive heat indicates a dead short....
Don't continue to use the switch, until you resolve the issue.
I suggest you use an OHM meter to test the positions on the new switch, first, and make sure it is not the culprit. (New does not=good!)
If that's o.k., then test each wire independently, by putting a 12v source on the wire....One source terminal to ground (+ or -, depending on your car), the other to the wire...
Have another person watch to see what light goes on....
This all assumes that you do not have a wiring diagram, with correct wire colors marked, or you cannot determine what your wire colors are, because of age and discoloration.
Good luck.
Edward
E.B. Wesson

I believe you should have:-

one "Brown with Blue" cable from the Ignition switch to the "A" terminal. I think this feeds power from the control box when the ignition is on.

three "Red" cables (Power to Aux lights) to the S1 terminal. One of the red cables goes to the fog lamps via the Panel lights and the other two feed the side lights.

and

one "Blue" cable to the Dip switch from the S2 terminal.

I guess the Brown and Blue cable is connected correctly if you are getting power when the ignition is switched on. The blue cable is connected correctly if the head lights work. One of the red cables is correct if the Panel/Fog lights work but one of the red cables must be connected incorrectly if the side lights don't work.

AJ

A R Jones

Hi Bud,
you should have 3red wires to S1 terminal, 1 blue to S2 terminal and a brown/blue to A (supply). If this is the case then the fault is elsewhere and may have caused the original switch to fail. Disconnect S2 and try the sidelights if OK then reconnect S2 and disconnect S1 and try headlamp. If fault is still there check whether the dip switch is faulty and putting main and dip together.
Ray TF2884
r lee

Bud ,
Above is good advise but....
Do you have a wiring diagram for the car?
If not let me know and I can get one to you via email.
At some point it will come in handy!
David Sheward

"At some point it will come in handy!" Dave has understated this - it should say - if you are going to fuss with the electrics in the car, a good circuit diagram is MANDATORY! among other things, it will keep you from being a DPO to the next owner of the car.

"excessive heat indicates a dead short...." This is only one cause of excessive heat. It can also be caused by a high resistance connection in the switch, either external (wires attached to the switch terminals) or internal, deteriorated connections or contacts inside the switch. Cheers - Dave D.

David DuBois

David of Ohio

I don't have a wiring diagram for the TF. As I have said month's ago I am new to the MG world and it is a learn as you go process. Another problem I have regarding the light switch is that someone has replaced all the dash wiring with red wire. They all look the same. I noticed in the reply some referred to S1, S2 etc. How do you determine which is which? I guess this sounds like a fooling question? But thanks for any help.
Bud W.
S.A. White

Bud ,
First things first ...lets get you hooked up with a diagram! That way you will be able to "see" what others are taliking about.
Contact me via :
hootersvilledavid"at"yahoo"dot"com
From there we can figure out what "format" will work for you.
Auto-cad would be great, if you can open the file.
Worst case I can scan the page from the WSM ...but my copy is kind of funky as my DPO made some "notes" and blead on it!

David Sheward

From what you say the headlights work when the ignition is switched on and the light switch is pulled fully out. Therefore the wire from the ignition to the light switch must go to the A terminal and should have been Brown/Blue not red. You can look under the dash to check this. Mark the A terminal before you go any further.

Disconnect the wires from the light switch and push the switch fully in (off). Attach one lead from an ohm meter to the A terminal you marked. Pull the switch out one click as though you are turning the side lights on. Check with the ohm meter which of the other terminals gives a closed circuit. This is the S1 terminal. The S3 terminal will only give a closed circuit when the switch is pulled fully out.

Hope that's clear and is of some help.

AJ
A R Jones

Just to note, a 12V test lamp with a probe, comes in mighty handy in situations like this, along with your meter.....
There are times when power is going to the lamp, but, because of ground or other connection problems, the lamp doesn't light....Using the test light at the socket of the bulb, will show if the power is getting there or not.
Frankly, if your wires are all the same color, the diagram will only work as a guide, but you will have to trace, and mark every wire to the switch with the color it is supposed to be...
I have done this on other cars, with colored tape and colored wire ties.
Edward
E.B. Wesson

Edward ,
Kind of my thought as well (the diagram will only work as a guide).
Short of a full re-wire, I was thinking if I get him the diagrams and wire "codes" he could pick up a set of stick on wire markers at any electricial store.
That way as he is tracing wires he could mark them with "code numbers" per the WSM.

Personally I would rip it all out and start over but I can understand were someone might not want to do that. MY dash was wired with all purple wires when I got my car. It "worked" but labeling them made the re-wire (and adding some fusing) when I pulled the dash out and had at it did help.

Soon as I get an email from Bud I'll get him hooked up with diagrams & wire codes ...having that should help make better sence of "S1 S3 ect" referances.
David Sheward

In case I'm not near my email.
I'll get you better resolution by email.


David Sheward

codes


David Sheward

Dave, my email address is right there next my name, just not clickable.
Anybody recall what issues of TSO had the centerfold style colored wiring diagrams? Bud
Bud Krueger

Bud K ,
I meant S.A. White, Alabama, USA, signed his post : Bud W.
You don't need diagrams ...do you?
Happy to send if you do.
David Sheward

I have a color Auto-Cad for TF and a second one I did for "My TF" with the mods & extra fusing I did.
This version is "pre-mod".


David Sheward

Bud K
The full color wiring diagram for the TF was in the October 2005 issue of STO. I believe they ran the TD and TC diagrams in the issues before or after.
I know because I keep it in the drivers side map pocket on my TF.
Hint....hint....I wish the TSO would run those again!!

Tom
'54 TF
Tom Norby

Thanks, Tom. Bud
Bud Krueger

Thank all of you for the help. As I told Dave I am located in an area (North Al) and there are no MG shops around. So I am more less dependant on guys you for any help. Thank again
Bud W.
S.A. White

Bud W,
You've got mail ...hope it helps.
Do note ...what I send is for "possitive ground car" as from factory.
David Sheward

If I am coersed enough I might be persuaded to copy the TSO diagrams full size with a color copying machine. Sent Snail mail, cost a buck apiece.
Cheers,
Bob
Bob Jeffers

Bob,

I will take two at your convenience.

Regards,
Jim

jneel43 at hotmail dot com
James Neel


James Neel -- You didn't say which diagram you wanted. Please be specific. Also email me off line with a mailing address.
Cheers,
Bob
Bob Jeffers

This thread was discussed between 04/03/2012 and 05/03/2012

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