Electrical Experts - Vixen 2500 - Ignition Switch Observation?

[Rocky_LC]

Hi Gang -

I had been having some intermittent electrical problems with the gauges on my 1971 Vixen 2500, (this condition was reported to me by my Previous Owner, while I was buying the car). For certain the Tacho, and the Temperature gauge work most of the time, but sometimes don't do anything at all. This intermittent condition MIGHT affect my fuel gauge as well, but I can't be sure, as that gauge almost never works, even with the other gauges are operating properly.

Anyway - just yesterday I noted that the problem is in the ignition switch... If I jiggle the switch just right, the car will continue to run, but the Tacho and Temp gauge quit working (both fall to zero).

I looked at my schematic from the users manual, but am not seeing a common connection there... I am seeing the instruments power comes off the fuse panel on the bulkhead. It's weird that the ignition will still run, but the gauges don't work.

Of course I need to lay down under the steering wheel, and need to look at how many wires are going into the switch body.

Anyway - any suggestions (other than look with your eyes, and not with your keyboard!)?

1) Is anyone aware for separate connection in the ignition switch for instrument power, and ignition?
2) Can I disassemble or clean up the electrical part of the switch without too much trouble?
3) Source for replacement ignition switches (but I'd like to keep the existing tumbler).
4) Other ideas?

Thanks -

Rocky

 

[mezy]

found a wiring diagram, if you look at the back of the ignition switch there should be a purple wire on terminal 4,
This feeds a 35 amp fuse which in turn feeds a shed load of things including water temp and fuel gauges.
on position 2 there should be a white wire that feeds the coil. sepearate to the gauges, thats why it will continue running.
if you put a good 12 volt feed to the puple wire and all the gauges work as they should, the problem will be the switch.

 

[DrEntropy]

Hiya, Rocky!

Not sure which column lock/switch you've got, but the switch assembly should be detachable from the tumbler/lock body. mezy sussed out the wiring, I will suggest trying to get some > CRC 2-26< into the switch body and working the switch through off and first position a few times (battery disconnected) before going through the replacement exercise. An interim remedy for certain but it may work until a replacement is in-hand.

The most common issue we found with those switches is the plastic/nylon "socket" the pin of the main lock fits into gets wallowed out over time and doesn't always engage the switch completely. "jiggling" the key will sometimes work the switch contacts to align. Only fix if that is so is replacement of the switch.

 

[Rocky_LC]

Thanks, Guys!

Great information…. I’ll check it.

First plan is to see if I can measure the loss of voltage in the purple wire. I definitely can make it happen on command with judicious key positioning!

Thanks again….

Rocky

 

[DrEntropy]

Let us know how this goes and what you find.

 

[Grantura_MKI]

I am hoping that this isn’t one of the ones fitted with two ignition switches.

 

[Rocky_LC]

Is that a real thing?

My car seems fairly conventional…. Key switch does it all…. Turn the key for power, one position further to engage the starter.

It has a cowling around the turn signal stalk, and dip beam switch, but IIRC (I haven’t really climbed under to look and my car is in remote storage), the ignition switch seemed fairly exposed on the steering column….

Thanks

Rocky

 

[Grantura_MKI]

Yes.

 

[Rocky_LC]

So I dug into my ignition switch today… (sorry I’m such a slug)…

It was pretty straightforward to get the entire lock mechanism and ignition switch off the steering column… except for the fact that I had one of those bolts that shear off on the top of the column, and a crappy 5/16”-18 bolt on the bottom…

I cut a slot in the top bolt with my dremmel, and very easily got the sheared bolt out with a flat bladed screwdriver.

I sprayed out the ignition switch with contact cleaner.

I found I have a Lucas 394150 Ignition Switch (same as the early TR6s). Best price to buy one is at Moss Motors (about $55).

Anyway, I’m going to see how the old switch works with just contact cleaning.

I cleaned up the wiring and used some new allen-head caps screws to mount thing ignition lock on the column.

I put some sheathing around the wire bundles. Everything looks a lot better now. My picture doesn’t do it justice. Everything is lubed and tied up as it should be.

Thanks for your help, dudes!

Rocky

 

[DrEntropy]

It seems you've got it well figured out. A great deal of what went into the build of your TVR in the way of electricals and some trim bits is in common with Triumph Spitfires. My mid-sixties Lotus Elans are the same. Nice job with the cap screws and with the wiring being cleaned up.

The switch in your second photo appears to have been disassembled at some point, the crimps holding it together have been opened and re-bent. If it came through our shop it would get a replacement, given the problem description and the "evidence of nobbling". Those switch bodies are potmetal; brittle and will usually crumble on a third attempt to bend those crimped edges out and back in again.

In addition to Moss, that switch is available through BP Northwest and Rimmer as well, not that much difference in cost. Beware of "white box" substitutes.

 

[Rocky_LC]

Yes, I noticed someone had been inside it…. I thought about opening it up again, but I figured if the contact cleaner doesn’t work, I’ll get a new one in the future.