TR2/3/3A ignition switch smoking

[pawpace]

I washed my TR3B engine compartment and under carriage. I was careful to keep the spray off the electrical components. When I tried to start it, nothing, no click, no engine turnover, etc.. I then noticed smoke coming from the ignition switch and immediately turned the switch off. When I looked under the dash, I could see a bit of burning on the brown/blue wire that goes to the headlight switch. It was burnt on the ignition end of the wire.

I don't see how washing could have anything to do with this but I am very weak on electrical problems so I added that since it happened after the washing. I don't want to cause new problems but should I replace this short wire and try again or am I looking at a new headlight or ignition switch? How can I check?

Thanks for the help.

Mike

 

[CJD]

It sounds like you have a short. The ignition switch was merely a victim. I would connect your battery through a 12v test bulb, and then start looking for the short. The 12v bulb will light whenever the system is under load, and will prevent burning out other wiring until you find the short.

 

[sp53]

I like that John, but let me see if I understand. So, the light acts as a device for the system to use temporarily if and when there is a short. I guess what I am seeing is a single wire being force across the battery, but having the light in the system right at the battery gives the battery someplace to use the battery current. Is that correct ? Would the whole electrical system be protected this way?

steve

 

[CJD]

That's essentially it. I use a little 12v test light. Take one of the cables off the battery, and then use the test light between the battery and that cable. With everything off, the light will be off. If you turn something on, it will both light up at a dimmer level, and the accessory will run at reduced power. If the accessory has a full short, then the test light will shine brightly and will prevent burning any wires to the short.

 

[pawpace]

That's essentially it. I use a little 12v test light. Take one of the cables off the battery, and then use the test light between the battery and that cable. With everything off, the light will be off. If you turn something on, it will both light up at a dimmer level, and the accessory will run at reduced power. If the accessory has a full short, then the test light will shine brightly and will prevent burning any wires to the short.

John, I found a frayed bn/bl wire right at the ignition. I replaced it but am afraid I got some wires screwed up and now I don't have any power to the switch. I have checked several sites for schematics and they show 3 white wires connected to the switch on one side and the bn/bl going to the headlight switch on the other side. I don't have that many white wires unless they are buried in the other wires and I can't see them. Working upside down on electrical is not my forte. Do you have a picture or diagram I can follow of the back of your ignition switch?

I am really grateful for all your help.

Mike

 

[CJD]

The corners of the center panel have thumb screws...so 4 total. The bottom screws are easy to reach, the uppers not quite as easy, but worth removing to pull the panel out of the dash enough to work on your wiring. If needed you may need to gently work the choke cable and temp capillary gently to get some room to work.

There is a diagram in the beginning of this thread:

TR2/3/3A - Electrical

I own a 1958 TR3A. I replaced the original wiring harness and I am now experiencing an issue/problem. In addition I replaced the ignition switch purchased from Moss with the four tab connectors. The other item replaced is the light switch. My problem or issue occurs when I turn on the...

www.britishcarforum.com

Basically, the power from the battery goes through the control box to the light switch...and is always hot. From there, a wire brings the power to the switch, which sounds like your BN/BL wire. Again, this is always hot, so if it is frayed, that could cause trouble.

The white wires are power out of the switch...so they run to everything that is switched. i.e. ignition coil, starter solenoid, generator warning light, and fuse A3. Then the wiper motor, fuel gage, brake lights and turn signals pull off this fuse. Since your fuse did not blow, you can concentrate on just the white wires...and of course the feed wire to the switch.

 

[bobhustead]

John
Am I correct that the white wire out of the ig switch that goes to the starter solenoid first passes thru the starter push button (where it turns to white-red) on the way to the solenoid?
Bob

 

[bobhustead]

Mike
I have a very good color coded large size TR3 wiring diagram that is available at prospero"at"colorwiringdiagrams.com. Per that diagram, the ig switch has a brown in as John said. The white wires out, in three separate circuits go to control box pole D (it turns yellow out of the ig indicator lite but is the same wire); fuse box pole A3; and the starter push switch. While you need to check all John specifies, look as well at the possibility that the ig switch is internally shorting the brown power supply to the dash thru the switch body or the start push button is similarly shorting its white wire to the dash thru the switch body.
Bob

 

[pawpace]

Mike
I have a very good color coded large size TR3 wiring diagram that is available at prospero"at"colorwiringdiagrams.com. Per that diagram, the ig switch has a brown in as John said. The white wires out, in three separate circuits go to control box pole D (it turns yellow out of the ig indicator lite but is the same wire); fuse box pole A3; and the starter push switch. While you need to check all John specifies, look as well at the possibility that the ig switch is internally shorting the brown power supply to the dash thru the switch body or the start push button is similarly shorting its white wire to the dash thru the switch body.
Bob

Thanks Bob, I will go there asap.

 

[sp53]

There only 2 lugs on the back of the ignition switch, the 3 whites on one side and the blue on the other. Something smoking through the ignition switch, I would guess was the blue brown wire grounding out. Which in my view probably toasted the voltage regulator and open the circuit at the regulator, so there is no power to the ignition switch. I would look at the back of the voltage regulator and see if the short fried one of the conductor strips on the back.

steve

 

[sp53]

Washing the car could have something to do with the problem. The pull vent has a drain at the bottom of the venting system. There should be a rubber hose at the bottom of the vent for the hose to drain the water away. If not, the water could go onto the dash panel and cause a short.

steve

 

[pawpace]

Washing the car could have something to do with the problem. The pull vent has a drain at the bottom of the venting system. There should be a rubber hose at the bottom of the vent for the hose to drain the water away. If not, the water could go onto the dash panel and cause a short.

steve

Thanks Steve,

I am still working on the problem. I will check and let you and everyone know if I solved the problem with the help of some good people on this site.

 

[pawpace]

Finally got the starter to working and fired her up. Now the turn signal lights don't work so on to that problem. The dash wiring is really screwed up according to the wiring diagrams. I bought this car in a basket years ago and I did all the restoration, including rebuilding engine. The one thing I did not touch was the wiring. I had a shop do that for me but I don't believe they got behind the dash because that was intact. They did they engine wiring so I could get it started. I believe it must have been the person that originally was going to restore. It was painted a bass boat green with all the big sparkles including the whole dash except the gauge panel. Just a little history of what I am working with. I really haven't had any electrical issues until now.
Thanks to everyone for all the help.

Mike