Headlight switch hot

[Nigel curry]

Hi all
The headlight switch gets really hot in my 1976 after a run,is this normal ( not had the car long and only noticed it on a 140 plus mile journey home from picking it up)and the lights were on a fair bit.
Thanks for any thoughts
Nige

 

[Dellb]

When I rebuilt my 80 C3, the headlight switch was cooked. During the rebuild I installed relays close to the lights, and fed the power side direct from the alternator. All the switch does now is to operate the relays. Works a treat with no overheating of the switch.

 

[Emc]

Nigel it will be the stat in the switch that's a dangerous fire hazzard

 

[Nigel curry]

Ok
Got it thanks lads,is this a repair jobby or am I looking for a new switch gav
Nige

 

[Emc]

Check the switch first, I do keep them

 

[Nigel curry]

I don’t want to sound to dumb!!gavin but
I have the switch out so how do I check against over heating , I know it works as the car was driven home at night and lights were on approximately an hour and and a half,and it was only noticed to be hot when the lights were switched off
Nige

 

[Emc]

I don’t want to sound to dumb!!gavin but
I have the switch out so how do I check against over heating , I know it works as the car was driven home at night and lights were on approximately an hour and and a half,and it was only noticed to be hot when the lights were switched off
Nige

If you can refit the conections then switch the lights on and watch it carefully

 

[Nigel curry]

Understood thanks for taking the time to explain to a novice willing to learn mate
Nige

 

[johng]

I don’t want to sound to dumb!!gavin but
I have the switch out so how do I check against over heating , I know it works as the car was driven home at night and lights were on approximately an hour and and a half,and it was only noticed to be hot when the lights were switched off
Nige

If it's getting hot that suggests there is a resistance somewhere, either in the switch itself or in the connections. The connections are easy to clean if you've got the switch out. You can also take the switch apart and clean the contacts inside.

 

[teamzr1]

To add what johng stated

The lights are causing a high current load, which causes the switch to get hot (if instead this was a fuse, it would have blown with higher amp draw)
Over time, that causes the switch to degrade, such as the thin copper strips you see of the contacts in the switch

Add switch over all that time with that current load those contacts due to heat began to bend a bit causing even
more resistance in switch, which you can see in the photo Johng supplied


Really, the switch over all those years functioned way longer than if should with that current load heat

You could just replace the switch, and it would last a long time, or maybe take it apart and try and clean it up, ( but if new switch is cheap in cost, better way to solve this) or

What the guys are saying is if adding relays to the lighting circuit would take away that high current load on switch
This is because now all that switch does is controls the coil in the relay, which has almost no current load
and the contacts of relay than handles the current load of the lights

 

[Nigel curry]

Bags of good info/advice
Thanks again lads
Nige