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TR2/3/3A Parking light fun - TR3A

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Sorry, I was unclear ... I think LU52240 is for the entire early assembly, including lamp holder, rubber housing, pigtail, chrome bezel and flat clear lense. Anyway, Revington's on-line SPC shows P/N 107593 for the early lamp, and TRF's database shows LU52240 as a substitute. Plate AC TR3 Head, side, tail lamps

The later "beehive" lamp is 117010 on Revington's SPC; which TRF crosses to LU52338.

One of these days, I'm simply going to have to scan my own SPC, so I don't have to rely on Neil's.
 
The fun continues -

Once again I tried the light switch, pulling one notch to "parking lights". Parking lights and headlights came on. Foot button changes from low beam to high beam as normal.

Smelled something get very hot very quickly. Immediately pushed the switch in (off). Traced the smell near as I could to under the dash.

Ignition is still off. Tried the switch again, smelled the same hot smell as both parking and headlamps came on.

As par for the course, panel wiring is "creative". Light switch (original most likely) has (Term#1) blue/white leading to ignition switch, (T2) blue leading into harness, (T3) green patched into a red leading into the harness.

Ignition switch has (T1) green leading to starter button, (T2) white leading into harness, and (T3) brown/blue leading to harness plus blue/white leading to light switch.

Most of the harness wiriing appears quite old, perhaps original. It's the bits leading to switches, lights, etc. that seem replaced. Tracing this is nightmarish.

I'm thinking of somehow figuring out how to completely cut out the headlamp/parking lights and just leave the turn signals. Car runs fine and turn signals work fine. It's the parking light circuit which is somehow "crossed" with the headlamps, most likely under the dash.

But there is no obvious cross linking of wires; even with the light switch hanging loose below the panel, with no other wires touching it, the problem continues.

Tom
 
So, stick your hand behind the dash, then pull the switch on with the other hand. The heat should very quickly lead you to where the problem is !
:^)

Your ignition switch has been replaced with a later unit, the original only had two terminals. But the wiring you describe doesn't seem too badly off (ignoring the odd color codes for the stub ends patched onto the original harness). The brown/blue into the harness is the power source from the control box, which is where both the ignition switch and the headlight switch are supposed to get their power. Only error here is that the original wiring had the brown/blue coming to the headlight switch first and then jumpered to the ign switch; but it won't hurt anything to do it the other way around as long as the jumper is stout enough to carry all the headlight current.

The blue wire from the light switch into the harness should be the power to the headlight dimmer switch on the floor. Assuming you don't want to burn yourself as above, try removing it from the switch. If the headlights no longer come on with the parking lights, the short must be inside the switch or on the terminals.
 
Excellent - thanks for tracing those wires. And for the blue wire disconnect idea.

I just disconnected it from the switch, re-connected the battery, pulled the light switch to Park, and only the parking lights came on. No headlamps.

Per your previous post, does this indicate the light switch itself is the problem?

Thanks Randall.
Tom
 
7:28pm. Pulled the switch. Seems very clean - maybe relatively new. Interestingly, there's a "burned" smell on the switch. I'm just about to try to test it.

Stay tuned ....

T.
 
Interesting - when the switch is off, there's no continuity among any of the 3 terminals.

Switch at first position (parking lights), there's continuity among *all* three terminals.

Switch at second position (parking and headlamps), there's also continuity among all three terminals.

Stupid question: is this the way it 'posed to be?

Tom
 
NutmegCT said:
Stupid question: is this the way it 'posed to be?
Click to expand...
Nope ! But it sure does explain what you are seeing.

It may be just that the stop for the first position is broken or damaged (on the original switch, you can see it move in a slot on the side of the switch), in which case you might be able to repair it. Look in between the 3 terminals and see if there is a small nut visible in the hole. On one switch, I was able to remove that nut and pull the center commutator out ... but then I discarded the switch after I discovered the heat had damaged the contacts and they no longer were 'springy'. Since you've already seen some smoke come out, I'd guess you're in the same boat.
 
TR3driver said:
Sorry, I was unclear ... I think LU52240 is for the entire early assembly, including lamp holder, rubber housing, pigtail, chrome bezel and flat clear lense. Anyway, Revington's on-line SPC shows P/N 107593 for the early lamp, and TRF's database shows LU52240 as a substitute.
Click to expand...
Not really a substitute; 52240 is actually the original part number for the complete front side/flasher lamp assembly (with "clear lens") for all but the earliest TR2 through the TR3. For Lucas anoraks, it is the model L488 lamp, and 52240 was used on a host of other cars, including the Nash Metropolitan.

TR3driver said:
The later "beehive" lamp is 117010 on Revington's SPC; which TRF crosses to LU52338.
Click to expand...
Again, correct! This lamp also was used on various early Minis, Triumph 10s and some other less common cars (using a "clear lens, lightly stippled"). NOTE: 53564, used on A-H 100-6 and earlier 3000 models, Triumph 10s and others, is essentially the same lamp except for the red lens (used as a stop/tail lamp).
 
Here's the switch; very shiny plastic and brass. Can't see a small nut anywhere - and the small screw holds in a spring which is over a steel ball. Also there's a picture of the rear of the switch (supported in a plastic cup). Again, no visible small nut. But apparently held together with brass "rivets".

The thing seems quite simple. Wish I could figure out how to pull it apart, find the problem, and repair it w/o wrecking it even more.
 
The EXTRA uesd O.E.M. Lucas Switch I have works as described above, first stop on two terminals there's continuity the last stop {pulled all the way on} all three terminals there's continuity. I`m hesitant to send you my spare as it is the only one I have, but if No one else comes to the rescue I MIGHT be persuaded. V.B. list the switch for $37.00, I`m sure it is of the same quality as the switch you have that went bad.
 
NutmegCT said:
The thing seems quite simple. Wish I could figure out how to pull it apart, find the problem, and repair it w/o wrecking it even more.
Click to expand...

Tom, it's already wrecked; what have you to lose?

As we used to say, "[Insert name of component] failed smoke test."
 
Ok, definitely a repro. Nice looking repro, but a repro.

I seriously doubt it can be repaired ... but I think the way to take it apart is to grind away the small metal disc visible in the rear view. That's where the nut was on the originals.
 
Aloha Tom,

As I recall, looking at the bottom of the switch, in the center between the three terminals, there is a small brass nut. The maybe a cover plate that needs to be removed to get to the nut. The nut is what holds the contacts to the shaft of the switch.

<span style='font-family: Times New Roman'>Just downloaded the second photo (the rear of the switch). As Randall points out, that metal rivot is where the nut is on the original switch.</span>

The screw,spring and ball are the detents mechanism for the two "on" positions.

You may also need to remove the knob to get the shaft out switch body. Usually on the under side of the knob is a button that you push in and you can pull the knob off the shaft.

These are generally stout switches so it may be repairable. If it isn't, by disassembling it you can see how it works.
 
I need to get a new lighting switch. So when I got home from work (around 7pm), I removed the faulty switch and capped off the three wires.

Re-attached battery, turned the ignition key, and voila!

The red ignition light came on, the yellow turn signal indicator came on, and the ammeter showed major load.

As the yellow turn signal indicator was on, I tried the steering wheel turn signals. Regardless of which way I moved the turn signal, the ammeter showed further discharge, and the yellow indicator glowed brighter. At least there was no burning smell this time!

After major analysis and deep brain cycling, I have determined that something is amiss.

I'm assuming (dangerous ...) that with the three light switch wires capped off, the parking and headlamp circuits are out of the picture now, but the turn signal circuit is still in the loop.

I'm also assuming there's now a wiring problem in the turn signals - likely in the one I just replaced.

Looks like I've got more troubleshooting ahead.

Thanks all.
Tom
 
I'm thinking it's time to start over with a new wiring harness. Somewhat expensive, and somewhat time-consuming (but not difficult) to install...but the peace of mind and the ease of future troubleshooting are -- as they say in the ads -- PRICELESS! /bcforum/images/%%GRAEMLIN_URL%%/wink.gif
 
Perhaps I'm an optimist, but I wouldn't start yanking wires out just yet. I still haven't heard anything that says to me your harness is hopeless; and replacing the harness isn't going to fix bad switches, or bad lamps, or bad connections (well, not all of them anyway).

You are quite correct, the turn signals should work independant of the light switch even being connected; except of course that the lamps still have to be grounded.

But first, I would concentrate on why you are seeing "major discharge" with only the ignition switch on. The ignition coil should only draw about 3 amps, which is only a small deflection on the ammeter. And with the turn signal switch in the center position, there shouldn't be any turn lamps on, including the yellow lamp on the dash.

So, be sure everything is turned off, and pull the hot wire off the coil. If you still see deflection on the ammeter, start hunting for where the power is going. Pop the fuses out of their holders (although only the one with the extra terminal next to it gets it's power from the ignition switch). If you still see a discharge, check all the lights then start feeling around for what is getting hot. The red light on the dash should be on, but it won't draw enough current to even see on the ammeter (around 1/6 amp as I recall).

Once that is solved, then focus on why the yellow lamp is on. It's normal for it to glow just a bit from the light from the red lamp (the colored plastic extends behind the dash so one shines into the other to some extent); but it should not be on brightly with the turn switch off. If it is, most likely the flasher is wrong, defective, or mis-wired.

BTW, when I checked at the local parts stores, none of them had a proper flasher for the TR3 even though they claimed it would work. Their "universal" 3-prong flashers just don't work right with the stock TR3 wiring. A Tridon EL-13 "electronic" flasher was the only one I found that worked right. Eventually I rewired the yellow light so it would work right with the generic 3-terminal flasher, but the stock wiring won't.
 
Pulled hot wire off coil, ammeter still shows large discharge when ignition is on. Nothing (lights, etc.) in use. Red and yellow indicators are on.

Pulled both fuses - now there's no visible discharge, altho' red ignition light and yellow turn light are on. Of course, parking lights still not on.

Always using Triton flasher - so shouldn't be a problem there. Flashers were working fine before this all started.

However ... this "red-light yellow-light big-discharge parking-and-headlamps-on" problem all started after I replaced the faulty left front parking/turn light assembly. The original one had a broken internal connector. Replaced it and tested it not-yet-mounted in grill. Worked fine.

The problem started *after* I screwed the light assembly back into the grill. Noticed the screw holes looked like they had been purposefully drilled (not centered - one of the three holes was actually not centered, and was cutting into the large light assembly opening).

This *has* to be caused by something wrong (shorting?) in that left front parking light assembly and/or mounting.

I'll get home from work around 7pm tonight and pull that assembly, test it again "hangin' loose" (but not touching anything), and start from there.

Thank you again! Onward through the fog.
Tom
 
Tom,

I sure wouldn't assume that the problem is around that front lamp. For one thing, with the main lighting switch removed and the turn switch turned off, there shouldn't even be power at that front lamp ! IMO there has to be a problem under the dash, possibly a combination of DPO-isms and your moving things around to remove the light switch.

The yellow dash lamp should have a ground wire to the tie point on the dash, and a light green (?) wire to the flasher. Although the flasher gets power any time the switch is on, it normally only supplies power to the yellow lamp when it is flashing.

However, the flasher is supposed to get it's power through that fuse you removed (green circuit), so there must be something else going on as well.

I would still look for the big current drain first; as that means something is getting hot and may cause further problems (not to mention running the battery down), as well as possibly leading you to the problem with the turn signals.

But, it wouldn't hurt to disconnect the wires at the flasher, and see if perhaps it is related to the big current drain.

Randall
 
I remember when my father told me in the late 1970's that someone else had a TR3A and wanted to check his wiring so they could figure out their own. He said sure. Mistake! /bcforum/images/%%GRAEMLIN_URL%%/nopity.gif The guy spent about half an hour going over them and thanked dad and left. When dad came to look under the hood of his triumph all the wiring was disconnected! Never worked right until 1980 when I spent six hours /bcforum/images/%%GRAEMLIN_URL%%/wall.gif(yes I said six) unplugging and plugging connectors for wiring until they were all right. Back then no WWW to ask for a diagram. MAKE SURE YOU LABEL THE WIRES! Sorry I couldn't help. /bcforum/images/%%GRAEMLIN_URL%%/eek.gif
 
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