Thread: Burnt out Headlight switch - Again!

Hey mate

When you get your Traxide Kit post up a pic of where you mounted your relays in this thread

Traxide Relay Mounting Points

I changed my wiring a bit, rather than running the main feed back to the battery I hooked straight onto the alternator. I'm not sure what side the alternator is on a Td5 but thats an option

Most auto sparkies would know that the longer the cable the less voltage you get. Instead of mine being close to 2m long it's only about 40cm

Originally Posted by Jock The Rock

Hey mate

When you get your Traxide Kit post up a pic of where you mounted your relays in this thread

Traxide Relay Mounting Points

I changed my wiring a bit, rather than running the main feed back to the battery I hooked straight onto the alternator. I'm not sure what side the alternator is on a Td5 but thats an option

Most auto sparkies would know that the longer the cable the less voltage you get. Instead of mine being close to 2m long it's only about 40cm

Ah yes, BUT Tim supplies some pretty heavy gauge wiring to the battery, It has a lot to do with cross sectional area of the wire too, not just its length.
I have 14,2 volts available at my trailer hitch anderson plug, the gauge of wire supplied with the SC80 means I have no noticeable volt drop from the alternator to the trailer Even through the anderson plug I haven't lost anything. Soldered joints are also a must.

JC

Yep. I have had mine fitted for a while now and no more melted switch blocks.
Thanks Tim.
The kit makes it so easy.
The annoying thing is the switch will be more expensive than the kit and now you need both.

After burning out the original switch and getting a price of about 220 dollars for a replacement .........I decided to fit a different type of switch and found a aftermarket type push/pull switch would fit for 15 dollars.
This worked with 135watt globes for four years and burnt that switch out too.
It was replaced with a similar type of switch and this time two Bosch cube type relays fitted just near the switch behind the plastic cover for the steering columb.
The bosch relays cost about ten dollars each.
No more problems to date.
My defender is a 1994 model and more than ten years later they were still selling defenders with the same well known and possibly dangerous problem.
No wonder toyota out sell the landrovers by huge amounts.

Originally Posted by 101 Ron

......
My defender is a 1994 model and more than ten years later they were still selling defenders with the same well known and possibly dangerous problem.
No wonder toyota out sell the landrovers by huge amounts.

I do think that headlight relays are a worthwhile improvement, which as you say is well overdue. But in reality the switches do not give trouble unless higher wattage bulbs are fitted, so it is hard to blame the manufacturers, and relays are not beyond reproach either - I have had a similar relay to the one you mention (Bosch) fail on my driving lights while running 55w bulbs! But at least the relay is cheap and readily available compared to the switch.

My view (although I prefer relay operated lights - NOT with the relay in the dash) is that the switch design is substandard - the fact that they commonly fail with only doubling of headlight current shows they are operating too close to their limit, particularly in hot and dusty conditions. It is possible that the real problem is inadequate testing in hot and dusty conditions - are these failures common in their major markets?

John

Originally Posted by JDNSW

I do think that headlight relays are a worthwhile improvement, which as you say is well overdue. But in reality the switches do not give trouble unless higher wattage bulbs are fitted, so it is hard to blame the manufacturers, and relays are not beyond reproach either - I have had a similar relay to the one you mention (Bosch) fail on my driving lights while running 55w bulbs! But at least the relay is cheap and readily available compared to the switch.

My view (although I prefer relay operated lights - NOT with the relay in the dash) is that the switch design is substandard - the fact that they commonly fail with only doubling of headlight current shows they are operating too close to their limit, particularly in hot and dusty conditions. It is possible that the real problem is inadequate testing in hot and dusty conditions - are these failures common in their major markets?

John

John,
I am not sure that is entirely correct. Mine failed with standard bulbs as have a few others I know of. Even with the Phillips low wattage globes (I changed to after the first melted) it was still getting very hot after driving for more than 1/2 an hour with lights on after I put the new switch in.
Since fitting the relays does not even get warm.

Originally Posted by CraigE

John,
I am not sure that is entirely correct. Mine failed with standard bulbs as have a few others I know of. Even with the Phillips low wattage globes (I changed to after the first melted) it was still getting very hot after driving for more than 1/2 an hour with lights on after I put the new switch in.
Since fitting the relays does not even get warm.

I am sure there are cases where they have failed with low wattage bulbs, probably because of poor quality control by Lucas (and their heirs), but for example mine lasted nearly twenty years before failing and convincing me to fit relays. I suspect the "open" design of the switch plus dust may be a factor, not seen in their primary market. Of course, with only the relay current the switch will not get hot and burn, even if the contacts are dusty.

There is no reason other than poor design or manufacture why the switches should fail regardless of bulb wattage - switches have been handling this sort of current without relays for over a hundred years. If they are fitting switches without relays they should stand up to it in all conditions, although you can't expect them to stand higher wattages. (But there are other good reasons for having relays to avoid the voltage drop from the amount of wire between the alternator and the bulb.)

John

I also own a 1960 model CJ Jeep with a old fashion push/pull head light switch in the dash board and foot dipper switch which has no relays and runs 135 watt light the same as my defender.
That switch has been operating for 49 years without trouble and the last 20 years with extra current going though it.
Jeep has no doors and the thing gets filled with dust and dirt.
Only the dipper switch has failed once or twice due it filling up with water after creek crossings up over the floor of the vehicle.
Jeep is a cheap production vehicle.
If jeep can do it why cant Landrover.?
The relays fitted to my defender up under the plastic cover for the steering wheel was done that way because the wiring itself is up to the job of running the head lights without any hassles.
Yes relays and a loom down at the front of the vehicle is better, but after looking at the wiring itself I couldnt see the need for the extra trouble and I have had no problems to date.
The silly standard switch is the problem with or with out lighting up grades.