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Returning to the TR fold...and a headlight problem


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#1 Ledgers

Ledgers
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  • Location:Perth, WA

Posted 11 March 2018 - 02:56 AM

Hello all,

A quick intro: I had a TR6 for about ten years, and was a regular visitor to the TR Register forum, mainly to learn stuff. I sold that in 2012, as the wife hated going out in it, and we got a Stag instead. We then emigrated to Perth, Australia, in 2014, bringing the Stag with us, and it is still a member of the family.

Recently we happened to walk past a house where there was a yellow TR7 with a For Sale sign. Having had no intention of getting another classic car...we ended up buying it as the seller was deperate to get rid of it, and I hope the price was right. It needs a fair bit of cosmetic work, mainly trim, new seat foams and sorting out a few electical niggles, but the engine, gearbox and drive train seem fine. It has new hoses, radiator and brakes.

 

So, to the point of my post: the off-side headlamp pod doesn't rise more than about an inch, and it doesn't drop back either. The near-side works perfectly. The light itself is fine. I have cleaned the earth and red plug contacts, and swapped the relays to no avail. However, I did notice that the circuit breaker was very hot, and clicking, and this resolved if I disconnected the red plug by the headlight. The pod does not rise if I turn the manual knob, and this knob is very stiff, so I am assuming the problem lies in the motor or pod mechanism somewhere. I can raise the pod fairly easily by pulling it up (when the light master switch is on) so I think the mechanism is OK and not jammed.

Would you agree that the problem is likely to lie in the motor? I don't want to remove the whole pod unless I have to and as I am not a mechanic/electrician I appreciate any advice before I get out of my depth!

 

No doubt this will not be the last question I have to ask here.

 

Cheers,

Ross


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Ross

Inca Yellow TR7, 1978, Australian

Tahiti Blue Stag, 1976, UK import into Aus


#2 bob-menhennett

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Posted 11 March 2018 - 10:17 AM

Ross

Welcome back  to the forum

A good check list is on here : - http://www.tr8archiv.../Headlamp9.html

Follow the instructions , usually it's poor electrical connections or lack of lubrication on the mechanism. A spray of WD40 or Aussie equivalent , might get things moving. Whatever you do, if the power is ON , keep your fingers well away unless you want to end up with one less finger than you started with !!

Good luck with it.

Bob


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#3 Alec Pringle

Alec Pringle
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Posted 11 March 2018 - 10:20 AM

Hi Ross,

 

if you go to the TR7/7 Forum and utilise the 'search' facility (top right) for 'this forum' and insert the word 'headlights'  you'll come up with a whole raft of discussions re the usual Wedgie headlamp gremlins

 

Cheers,

 

Alec


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#4 Ledgers

Ledgers
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  • Location:Perth, WA

Posted 11 March 2018 - 10:50 AM

Thanks guys, nice to see some familar names already.

Bob, thanks for the link, not found that site in my Googling this problem

Alec, sorry to hear about your health, hope the latest treatment works. I have probably read every headlight topic in the forum, using "search", but none seem to relate to my issue. I appreciate the potential similarity in underlying causes, even with different symptoms. As the manual knob doesn't lift the light, I'm assuming mechanical rather than electical.


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Ross

Inca Yellow TR7, 1978, Australian

Tahiti Blue Stag, 1976, UK import into Aus


#5 Darth V8R

Darth V8R
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  • Location:Portland, OR USA
  • Cars Owned::1974 TR6
    1980 Mini
    1980 TR8
    1976 TR7

Posted 27 March 2018 - 11:08 PM

Hello all,

A quick intro: I had a TR6 for about ten years, and was a regular visitor to the TR Register forum, mainly to learn stuff. I sold that in 2012, as the wife hated going out in it, and we got a Stag instead. We then emigrated to Perth, Australia, in 2014, bringing the Stag with us, and it is still a member of the family.

Recently we happened to walk past a house where there was a yellow TR7 with a For Sale sign. Having had no intention of getting another classic car...we ended up buying it as the seller was deperate to get rid of it, and I hope the price was right. It needs a fair bit of cosmetic work, mainly trim, new seat foams and sorting out a few electical niggles, but the engine, gearbox and drive train seem fine. It has new hoses, radiator and brakes.

 

So, to the point of my post: the off-side headlamp pod doesn't rise more than about an inch, and it doesn't drop back either. The near-side works perfectly. The light itself is fine. I have cleaned the earth and red plug contacts, and swapped the relays to no avail. However, I did notice that the circuit breaker was very hot, and clicking, and this resolved if I disconnected the red plug by the headlight. The pod does not rise if I turn the manual knob, and this knob is very stiff, so I am assuming the problem lies in the motor or pod mechanism somewhere. I can raise the pod fairly easily by pulling it up (when the light master switch is on) so I think the mechanism is OK and not jammed.

Would you agree that the problem is likely to lie in the motor? I don't want to remove the whole pod unless I have to and as I am not a mechanic/electrician I appreciate any advice before I get out of my depth!

 

No doubt this will not be the last question I have to ask here.

 

Cheers,

Ross

 

Visit this site for a lucid explanation of what the headlights are thinking: http://www.team.net/.../headlights.htm

 

It usually a bad diode, bad relay, or perhaps a bad switch in the headlight motor assembly. You can test them without removing the headlight by disconnecting the harness inside the engine compartment behind the offending headlight. Use a schematic, all the wires are nicely color coded. There is a nice schematic, by the way, on the referenced web page.

 

1. Swap the relays in the glove box between the two headlights. You said you already tried this, so you have completed step one, and ruled out the relays.

2. Disconnect the harness to the headlight assembly. Probe the wires going to the motor assembly using the diode test function on your meter. The diodes should read roughly half scale in one direction (or  0.7 volts if your meter reads out in volts while testing diodes), and open in the other. Beware that the diode can act very flakey, and your meter can show it as good, but it will fail when hot, or under load. But it is a good first check. Be sure to test both diodes in both directions.

3. If the diodes pass, repeat the test with the headlight in the up position (harness still unplugged).

4. If your diodes fail open, remember that the motor switch can also fail open, so when you open the motor switch assembly, restest the diode and the switch.

 

I had a diode fail open in one of my headlights, and it went intermittent before failing completely. When a diode fails open, the motor stops getting power while raising or while lowering, depending on which diode fails (there are two per motor). If a diode fails shorted, the headlight cycles continuously until you disconnect the plug.

 

I am pretty sure you will end up pulling the headlight assembly to fix it. The good news is that it is trivial.

 

Keep us posted.

 

Vance


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#6 Ledgers

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Posted 31 March 2018 - 07:30 AM

Thanks.

Just to complete this thread for anyone searching in the future: the problem was a seized bracket (the one the headlight pod attaches to).

Did most of the electrical checks, then removed the pod and it became obvious what the issue was. Strip down, free off, lubricate, reassemble, reinstall and adjust.

 

Did the same on the other side and found the "member" that attaches to the car was different, it has a catch that allows the moving bracket to move one way only, unless that catch is manually retracted. From a Lotus, maybe?


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Ross

Inca Yellow TR7, 1978, Australian

Tahiti Blue Stag, 1976, UK import into Aus





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