New Headlight Switch but no Lights

[Soup]

Installed a new headlight column switch today in my 72 Tr cause the original was definately broken. Ever since I got this baby running, last summer 4th of July, I've never been able to drive her at night and I love a late night drive with the top down.

So I put the switch in and nothing. I shouldn't say nothing, I did get a little smoke from the fuse box and immediately shut the light switch off. The high beams do, however, work when I pull the lever back but with normal operation nothing works.

The smoke came from the terminal closest to the wheel well (or Bottom) and those wires are two red and one red/green. I believe from the scare on the fuse that the smoke was coming from the side of the terminal where the two red wires connect. These wires are the ones that feed the exterior marker lights. So I disconnected the dual red wires from the fuse box to see what would happen and I still got nothing.

The problem for me is I don't know what else to check. I have so far double and triple checked the column switch wiring under the dash and everything looks right. I have also by-passed the high/low beam switch (dip switch) with a jumper but that did nothing. I did this because it appears that everything goes from the column switch to the high/low switch. I did a cursory check of all the marker lights and everything looked ok. Obviuosly something is wrong.

Any and all suggestions welcome!!

 

[RomanH]

That is odd since according to the circuit diagram in the Bentley manual the head lights are not fused. The fuse position you describe is protection for the running lights and the instrument panel lights. I have no idea why that fuse would get so hot when you try the low beams. Sorry. I think you are going to have to dig deeper to find the problem. /bcforum/images/%%GRAEMLIN_URL%%/frown.gif

 

[DNK]

according to what I see. It gets it's power from the Ign. and what I think is happening there is a problem with your running lights so when you turn on the lights (wait a sec,I should preface this by asking if anything happens when you turn on only the parking lights?) If yes is sounds like a problem down that stream.The R?G wire feeds the parking lights.

 

[Soup]

DNK, to answer your question, no nothing happens when I turn on just the running lights. Nothing happens in either switch position. I haven't checked to see if I get smoke from the fuse box if I just leave the switch in the running light position. I did get the smoke when I had the switch in the full position. I guess if I did do that it might narrow it down even more to the running lights?

At any rate it does appears to me that the problem is in the running lights since the green/red wires run this part of the system and since the running lights need to be on simultaneously with the headlights.

Can anyone recommend a type of tester that would help in diagnosing/locating the problem?

 

[Bugeye58]

Soup, you need to get some type of a multimeter. They will run anywhere from a $15.00 cheapie, which will probably be adequate for your needs, to as much money as you want to spend.
I wouldn't <u>think</u> of trying any electrical diagnosis without one.
Jeff

 

[Soup]

Bugeye, thanks, I'll look into one ASAP.

 

[DNK]

A thought try unplugging the G/R wire at the fuse box. Have someone to help you. Then turn on the switch. Do you have headlights? Is there smoke. That will tell you if it is downstream to the red wire,parking lights.

 

[Bugeye58]

I just <u>love</u> troubleshooting by the "smoke" method. /bcforum/images/%%GRAEMLIN_URL%%/grin.gif
Jeff

 

[DNK]

It's Lucas, It's in the manual

 

[Soup]

DNK, I had already tried disconnecting the red/green wires, since they are my smoking gun, to see if I would get the headlights to work and still got nothing.

I am getting power to the column light switch from the ignition. From the column switch power is sent to the high beams which do turn on when the switch is pulled back and power is also getting to the glove box which is also feed thru the column switch. So I figured it must be in the high low beam switch on the floor (dip switch), wrong. When I used a jumper wire to bypass this switch I still didn't get the headlights to go on.(?).

Still trying to figure this thing out.

 

[DNK]

My guess is the low beam wires are toast. Try something else. Unhook the wires from the switch and feed battery voltage to the lights. If it sparks like crazy then there's a clue. If that doesn't work call Dan Masters,he'll have ideas.What happens if you feed 12v directly to the parking lights? I think there is a chafed wire.

 

[Soup]

Let me make sure I'm undersatnding your suggestion; Unhook the wires from the column switch and provide a jumper wire from the battery to the wires under the dash to see if it sparks. Basically bypass the column switch.

 

[Guest]

Soup, what general condition is your total wiring harness in? Have there been any modifications to the stock harness? Do you have the correct wiring diagram for your year car?

I guess what I am saying is are you in need of a new harness? Shorts in the wiring system are usually indicative of a system that has seen a better day - corrosion, bad grounds, abraded wires, previous short circuits, modified wiring by DPO, etc. I know this sounds like a part-changing fix, but rewiring your car is often a good thing because it gives you the chance to completely familiarize you with the entire system and make everything right. This is doable in a long weekend. The fact that you haven't had headlights for a while is a great concern to me.

One of the best investments you can make is Dan Masters' book on electricals for the TR6, available from Moss or direct from Dan.

 

[Tinster]

Soup,

I am one of of those non-auto mechanic guys.

I bought three multi-meters and never could
understand how to use them. Fried two of the
them with smoke and sparks.

But it DID mange to remove/ replace every 100% wire,
switch and light bulb in my TR6 by using a motorcycly
battery for current and a screwdriver thingy with a wire
and clip on one end and a small light inside as my
testing device.

100% of the electircal system in my car is now functional.
Hope this helps out a bit. It ain't fancy but it works.

dale

 

[DNK]

Soup- That is exactly what I am saying. And I totally agree with Dr. Bill.
By providing power straight to the headlights you'll see if there is a problem there.
Then unhook the R/G wire from the fuse box and hook direct power to there.

 

[Tinster]

Hey Soup :

Listen to the wise folks here and take it to heart.
Sometimes the DPOs have so badly butchered the elcetircal
system yer better off purchasing a whole car wire harness.

PDO Pedro had my car wired with all black wires or stereo
speaker wires. None of my exterior lights or horn or interior lights functioned.

I bought the entire car wire harness at:

https://www.advanceautowire.com/

I totally disagree with Bill though "'This is doable
in a long weekend." Maybe if you wire cars for a living
it is. Mine took 4 months of 3 hours every day, mostly
becaue I had to gut all the black wires and run news wires
with nothing to follow.

You will never regret a full car rewire done with your own
hands. The educational value is priceless. Like when my
brand new temp gauge suddenly pegged out at 250* yesterday.

But my infrared gun (yes, always have one in my trunk Shawn)
indicated 180* normal temps. I knew instantly the ground wire had slipped off the back of the temp gauge. It had.
Gauge dropped back to 180*.

Long story short, get a motorcycle battery to provide actual loads to run down broken circuits and a for-dummies circuit tester lamp. Consider a rewire. Copper corrodes inside the
plastic wire covers over time.

d

 

[Soup]

TR6 Bill, unfortunately a wiring harness is not in the Tr budget for this season, neither is time. It seems I'm a little bit more strapped for time than most in this forum based on the accomplishments I see. Four young kids keep me pretty busy (10, 4.5, 3 and 1.5 years of age). Today I came home to one with a stomach virus.........looks like its going to be a long night. ;>( Really not complaining, wouldn't trade them for clean Tr anyday!!

Back to the topic, I am totally in agreement with re-wirirng the car and I completely agree with the fact that it will really familiarize me with my car, my hobby. I just don't think this is a good time for me to take on this type of project since one would want plenty of near uninterrupted time. Cash could also be an issue. What would someone guess the price to be? Six hundred?

First I will put more time and energy into trying to resolve this problem. The suggestions above may prove benficial. If not, I will be forced to seriously entertain the big picture.

Tinster, I'm with you on the whole multimeter thing. Need to read up on this gadget. Probably should've bought the simple pen light type.

 

[Tinster]

Soup-

You are fairly close on the $600. Make sure you purchase
all the required British crimping tools, bullet "pushers.
etc. Don't cut any corners on the british bullet connectors
to save money. Wait until you can afford the entire car harness and tools.

I'll gladly lend you all my British wiring tools when you decide to rewuire.

d.

 

[bailee2]

Do the tail lights work?
If so, the headlights are on the same switch circuit.
check your bulbs, sometimes the high beams will work when the lows will not indicating bulb failure.
Then go from there to the parking lights.

 

[Soup]

Tin - thanks for the offer on the tools but I'm the type to buy my own figuring I'll need it again someday anyway.

Bailee - Not a one of my running lights work. I did replace both headlights just because. I haven't replaced any other bulbs. I suppose I should pull them all and test them.