Head lights

[shaunmorris]

Hi,
I think my Cerbera has had a HID conversion in the past, problem I have is that when I switch on the side lights the dip beam also comes on. switch to dip beam and both stay lit, lift to main beam with the dip switch, this works fine.
I need to MOT the car, so this needs sorting, but I have no clue where to start looking.
I read an earlier thread about cutting the black and red wire from the dim dip control box, tried that and ended up with no dip beam at all.
Any ideas ?

Cheers

[ukkid35]

i have exactly the same problem, so very interested to find out the underlying cause

[shaunmorris]

I have removed the HID kit and replaced with standard H4 bulbs, now I find I have no dip beam at all, I must admit the dim dip control box does look worse for ware, perhaps there is an issue with that, any thoughts ?

Cheers

[tofts]

All these work arounds and other stuff is nonsense, no need to work around it, the system works perfectly as designed 20 years on, the failure is by the way of corrosion causing a runaway high resistance fault on the connections. Repair the connections and ALL of the faults disappear.

I have made a handy chart for fault finding cerbera (and most TVR) wiring faults:

Flickering lights? - Clean and Renew connections as necessary
Some lights not working? - Clean and Renew connections as necessary
Low voltage at the lights? - Clean and Renew connections as necessary
Intermittent lights? - Clean and Renew connections as necessary
Dim Lights on front of car? - Clean and Renew connections as necessary

This includes, earthing points, light connections, control units and interconnects.

Ok, now thats clear, one point I wish to make is that there is NOTHING wrong with the current carrying capacity of the original connections. The problem is corrosion and 20 years of fatigue, again follow my helpful chart above.

If you want your car to be reliable, do it once and do it right. Don't bypass things because they don't work. Remember it did work from factory so take the time to figure out why it doesn't work all of a sudden, don't just bypass it as that's just downright lazy. If your unsure as to why it doesn't work or can;t figure out the cause, then a half assed bodge with some poorly made solder joints and some choc blocs, whilst may work, will eventually fail. I guarantee this, as I see this time and time again.

Also a a point I need to make, when referring to the widely available diagrams for these cars.
THEY ARE WRONG!
Under no circumstances assume they are correct as they are not, double check with a meter EVERY TIME!

Again just to reiterate, 90% of problems are because of poor joints, the last 10% of problems are often result of failed control units. Guess why? Because of poor joints and additional stress this causes on the control units due to higher current draw and heat!

Oh and any body running HID headlights.
DON'T
Its an MOT fail as the housings and surrounding material are NOT designed to dissipate the heat correctly and can result in a fire hazard, not to mention that some of these cheap Chinese ballasts inject some interesting transient currents and noise on the cars electrical system which in turn can kill other control units. Oh, and a retrofit in to old housings will result in incorrect beam pattern and additional glare to other road uses which is unsafe and unfair.

Edited by tofts on Friday 23 November 21:53

[tofts]

Penelope Stopit said:

You are out of your depth

Subjective. But my post is based on several years of my direct experience on Cerberas, their looms and all related TVR control modules.

what you propose is beyond the knowledge of most to do correctly. I Will submit that the design could have been better, but the fact is that it did work, and in perfect order, still will. This is my point. I'm not discouraging change, and in fact people blowing up control modules due to something going wrong only serves to benefit me, but I would rather educate and help people solve an issue than fix their mistakes.

[shaunmorris]

The problem was a burned connection to the headlight switch control box, once this was repaired all lights worked perfectly.

Thanks you all for your help.