problems with early viscount tail light wireing

[chops]

Hi all,
Simple problem that sort of has me stumped,tried to wire up new lights today,a simple job,untill i plugged the van up to the car!
with the lights on,all is good.
with the hazards on,all is good.
press the brake pedal and it all turns sour,the blinkers come on and the brakes flash instead.
Now i'm guessing that theres a short somewhere,because its a late 60's viscount,with the ally body,where should i run the earth from and to,any tips or advice would really be a great help.
I've run all new wire from the tail lights thru to the hitch,what the bloody hell have i done wrong?
thanks guys and gals.

[Geoff & Jude]

hi chops

your problem will more than likely be as simple as a bad earth.

the reason it only happens when your brake lights are on is because they draw more current than the normal lights. this means that the higher return current through the bad earth connection cannot be made easily and is dispersed through other connections, causing the other lights to come on.

ali vans usually use the aluminium body as their principle earth and only run power to each of the lights.

the earth is created by the screws holding the light fitting to the ali sheeting and one earth connection from the connecting plug to the chassis or the ali sheeting. the problem is more than likely increased when sheeting is removed and the joints are water sealed when replaced, which could stop or reduce electrical conductivity between individual sheets.

there are two options.

go to each light fitting, loosen and re-tighten the mounting screws (after spraying some wd40 on them) or run dedicated earth wires to each light.

the first method is the easiest but the problem may re-occur later down the line and the second option will probably resolve the problem permanently.

your problem was a common one on many cars, particularly the later 'h' series holdens.

geoff 'n jude

[Rattles]

The best way of fault finding is to use a simple test lamp, all you need is a simple test lamp (see Image below) and a length of wire with alligator clips on each end, Connect the lead to one side of the lamp/wire under test and use the lamp to do the test, if testing a lamp the lamp under test will glow in series with the test lamp (both Glow) and depending on the wattage of each lamp one will be brighter than the other, but it will still indicate continuity, if the lamp checks out then check from the other end of the wire connected, TIP-: A higher wattage lamp in most cases will give a better test result.

An old Tail light / Fog light etc may be substituted for the lamp and holder or even solder wires direct to a Bulb.





If you need more help understanding the above PM me and I will be pleased to help.

Rattles

[chops]

Thanks guys,rest assured,a couple of beers and 5 minutes of peace and quiet,i'll be all over it,much appreciated.
once again,thank you.

[greedy53]

the viscount van don't have a earth wire to all lights the van is the earth and over time it just gives out,the best and simplest way to fix is to earth the van frame and body with the earth in the cars plug,than go and put earths on all lights,it really is a bad idea but they didn't expect them to be still working 30 years later
GOOD LUCK

[chops]

Hi guys,
Well i got my 5 minutes to play on the van and hey presto,earthed the tail lights and number plate light,and problem solved,there is still a very slight dimming,but im okay with that,one step closer to being towed down the road with the Valiant.
Thank you guys.