My car was stolen and they took most of the wiring from the engine bay and around the ECM. I rewired it for MUCH less wiring and has been working great for a few years. This winter I pulled the car apart and forgot I left the key in the ON position/ 1 click clockwise (not ACC or 1 click backwards/counter clockwise) for a few months. I just went and hooked up the battery and tried to lower my windows and Im not getting 12v to the motors… Im also not seeing any dash gauges move or buzz noises when I turn the key. My gauge lighting still works but I checked my Switched 12V distribution block and Im not getting any 12v to it. My gauge lighting, interior lighting and power locks work but not anything that runs off a switched 12v. I think its weird that I left the key in the on position for like 6 months with no battery hooked up and this is what i get?

I verified that all my hook ups are correct, no blown fuses and still can't get switched 12v. I think it has to be the ignition switch (not the tumbler) that has been replaced a few years ago.

what do you guys think? the ignition switch is on the column? Its an 1987 formula 350 and I see a part number of #US131T

 

I'm actually seeing a crap done of different part numbers.

US131
US131T
US105
US105T

Im assuming the T at the end means "tilt" steering column which is basically the column with the lever that allows you to tile the steering wheel up and down correct? But Summit has the US105 labeled as column with tilt.

 

Check fusible links? Should have 12v on C100 A4 (engine side), iirc the fusible link goes to starter lug.


http://www.austinthirdgen.org/mkport..._1987_C100.gif

 

THere is no longer a fusible link… I just pulled the column and going to physically test the ignition switch. It still makes distinct clicking noises in each key position.

I use the ignition switch wire to power a switched 12v distribution block and a fusible switched 12v block… my starter is a remote solenoid style.

 

That simplifies things.


I couldn't tell you anything on the part number as I don't know.

 

Well I was able to manual test the switch and it seems to be all working except for the "off" position.

I looked through the manual schematics and found that the car does not break down the ignition switch or tumbler to any great depth.

The tumbler has 5 positions:

Accessory mode: key is inserted and rotated 1 click counter clockwise
Lock mode: This is the position when the key can be inserted and removed and the steering wheel is locked.
Off Mode: This is the first click after inserting the key and rotating it clockwise
Run Mode: another click forward and is the position the key will be in when car is running
Start Mode: Last rotation after run when starter is engaged.

Now Im getting all the correct power to the yellow, Red, Brown and pink wires for the Accessory, Run and Start positions. BUt IM getting no voltage at any of the terminals in the "off" position which is the first click after inserting the key… or the "switched 12V" position. I just want to confirm with someone here that if you put your key in and turn the key 1 click that your gauges and door windows will work? You should also hear the key buzzer and other things happening.

There are a few wires that do not get any voltage or anything during the testing, those are… double green wires to 1 terminal (small gauge wires) and brown/white stripe (small gauge wire). Also I am getting 12V only in the run position from the Orange wire.


Breakdown of wires and voltages during key testing:

Orange= 12v in only run position
Double green wires = NOTHING
RED = 12V input from battery
Brown/white= NOTHING
Yellow = 12v in start position only
Brown = 12v in run and accessory position only
Pink = 12v in run and start position only.

 

Well I guess I figured it out. I picked up a new igniton switch and verified my original was still working correctly. I miss labeled a connection and didn't hook it to the battery and that's why I didn't have poweR. I rechecked everything and seems to be working now.