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TR2/3/3A Blowing a Fuse

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It is anomalous what tr3 wiring can do to the human spirt especially when it all worked fine just the other day. It makes me think philosophically that life is test. Anyways, I am thinking from what I hear on your description about the new harness and everything that the problem is in the control head. In the past, I have marked the wires then unhooked them at the steering box plus the grub screws, and slid the head out and actually did small repairs without removing it completely , but I cannot remember what I fixed exactly, but I had to move the indicator arm onto one of those brass stud so the stud would stay put to fix something. Not much help there, but keep us posted I like a good ending.

steve
 
Thanks and will do (report).

The steering control head, etc., hasn’t been touched since 2019, when I had Macy’s Garage rebuild the drivetrain and install a Moto-Lita steering wheel along with a new steering harness. The turn signals and horns have worked since, until the turn signals didn’t (and show a short) starting several days ago. I’m going to follow Graham’s lead and check the bulbs and holders first, then work my way back. It’s possible, too, that there’s some wear on the steering harness someplace in the tube...
 
OK, while waiting for wiper motor replacement brushes, I started “testing” the turn signal short circuit per Graham’s suggestion. Rear turn signals are LEDs with load resistors, front turn signals/side lights “regular” bulbs (amber). Key on, turn signal lever R or L and test bulb glows brightly and “kind of” flashes rapidly. Removing one or more LEDs, no change. Remove LH front bulb and test bulb barely glows but does pulsate when LH signal activated. RH signal activated shows short. Reverse procedure with RH bulb mimics the LH side test. Both bulbs out, test bulb barely glows regardless of LH/RH signal activation.

Ideas and suggestions?
 
Wiper motor success. New brushes arrived (expensive little buggers!), motor/housing cleaned and put back together. 12V test has motor running. Time to re-install in car.

Still need to run down the turn signal indicator short. A hint surfaced with a faint "zzzt-zzzt" sound when the RH bulb was inserted back into the socket. That could be the short. More to come...
 
The turn light fixtures are a common source of shorts, but that would be only with the turn signals "on". Next likely would be the trafficator and/or the wiring in and out of it. With everything turned off, you should be able to follow the short by breaking the connections into and out of the trafficator and testing both sides with an ohm meter.
 
Update: I narrowed the problem down to the control head. It's original to the car, and I've never worked on it. I decided to replace it with one from TRF on sale. It arrived today and I double-checked that installing it would fix the problem. I connected the four leads and tied it to ground. Horn works, turn signals work, everything works. Hooray! Now, I get to have fun installing the new control head!

Once the old one is out, I may take it apart and refurbish it. Or, I might have a beer...
 
Good news Keith. If it is original, perhaps getting a stator tube and a control head together as one unit might be an easier remedy. That way all you need is a new olive for the seal and some new oil and you are out of there. In addition, I would refill the shaft from the hole on the column rather than hole on the steering box itself. That way the back bearing is oiled plus it is easier.

steve
 
Update/Resolution. I replaced the control head with a new one from TRF. It’s very-well made and works well. I had trouble with one of the three grub screws, which was frozen in the hub. I drilled it out and the screw split in two, coming out easily. I chased the threads with a 10-32 tap. I got allen-head set screw replacements at the local hardware store; if you want pointed ones, I suggest McMaster-Carr. The Allen-head screws are much easier to use. I suggest 3/8 inch length. Feeding the wires down the stator tube proved to be easy; I had attached a string to the old set pulling it up through the tube when I removed the old control head, then used that same string to pull the new wire set down the the tube, with the help of my lovely wife/assistant.

The disk on the TRF control head was just a hair too large in diameter to fit in my MotoLita steering wheel hub! The inside diameter of the hub is just under 3 inches and the disk was just over. I used a caliper to measure and my Dremel to grind down the disk’s diameter as carefully as possible, to maintain an even circle. Lots of grinding, but I got it done. I lined everything up, slid it in, replaced the grub screws using a long hex-head screw driver, replaced the nut at the bottom of the steering box, connected the wires and tested everything. Voila! Horn works, turn signals flash and they self-cancel.

In getting out the old control head, the cast ring cracked and the brittle Bakelite came apart, so I won’t be reusing it. It was caked with some white grease that had become semi-solid. I’ll salvage what parts I can and add them to my control head stash.
 
Yes good news Keith. The control head is one of the fiddliest deals on these cars. Glad you got to the other side in style, nice job.

Steve
 
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