Flipping headlight issue

[rjgreen]

I have a dysfunctional headlight pod... can anyone help me?

The left headlight pod has lifted once since i bought the car and is the only thing that i can reliably say is gonna fail me an MOT. Its a 1984 DHC 2.8 and has the early wiring (in the bible its the same-ish as the US wiring)

The main problem seems to be that the relay which controls the LH motor will not switch in situ. So i have checked the following:

• tested the relay - it works fine (i've swapped it around in the panel and it always works)
• tested that the voltage at the relay pins is correct when opperated - it is same as RH relay
• tested the resistance of all the connections - negligable
• tested that the motor works when powered - it does

All in all the motor works, the wiring works, the motor control relay works and the actual motor relay works! What am i missing?

[alex290568]

Rich

I'm no expert but one thing I can advise you is that the headlights do not have to "pop up" to pass an MOT. If you wind them up and they are able to turn on and off in the correct allignment then your car will pass an MOT. Someone more knowledgable will be along shortly to advise you that your problem is a bad earth!!

Cheers

Alex

[rjgreen]

Aye, its true that there is no need for the thing to be working for an MOT. Overdramatic i agree but its buggin me... plus i have some really bad 80's trim to fix before the missus will get in the car

Regarding the bad earth, i can confirm that every earth that is connected to the motors, motor controllor or relays is earthed real good. Twas the first thing that i tested and the first thing i forgot to write on my list of tests

[Wedg1e]

Seen this?

http://www.wedgeneering.co.uk/TVR%20390SE%20p6.htm

[rjgreen]

Thanks for that, he's since stuck this on the TVR club site too (in a more readable format). Unfortunately i've been through all the errors that i can figure from the cirucit diagrams and everything seems to work (well bar the relay dispite having the same voltage at each input terminal as the other headlight relay which happily switches away).

[Wedg1e]

Almost certainly a fault with the motor's internal switch or diodes then.

[rjgreen]

Cheers, I'm gonna have a look at swapping the motor over to the other side and see-ing if it works over there. If it doesn't then its the motor internals, if it does then its possibly a dry join somewhere (weekend discussion with someone knowledgable suggests that i might get voltage until i try and draw current which seems to be the issue).

On the plus side its giving me lots of reasons to take out the mounts and clean them up