Headlight Connector Melted!!!

[CMF_BeeBoop]

Hello my friendly Micra folks,
I have stupidly fitted my '95 SLX with 90/100W globes.
Now they were fine for the first 4 months, then occasionally at night i would notice my passenger light suddenly come on, but i hadn't even noticed it was off. That went on for about a week until it no longer worked. I went to remove the bulbs and to my horror found the connectors were nicely adhered to the bulbs! I got them off and changed back to stock globes and now the passenger lamp only works if you give it like a little Fonzerelli tap. Okay, now i know i am going on and on, but only because i want the correct answer to my question. I was looking on ebay.co.uk the other night and ended up in some K11 review thingy in used-cars warning potential buyers of the more commonly known issues with my favourite little machines. And one was saying that the headlight connectors are known to melt. I think they were saying this is due to a poor earth. When i was at the local wrecker today salvaging some new ones i noticed one out of the two micra's there had already been fitted with dodgey after market H4 connectors.(So they must have melted too.)
So now, i ask YOU my experts what do i need to fix before fitting my new connectors? I don't want this happening again!

Thanks!
BeeBoop...

 

[CMF_frank2]

imo its mainly caused by people not squeezing the sides of the connector so remove them properly (and butchering them off instead )

 

[CMF_mipcar]

It's resistance that builds up with age and corrosion on the contacts.
Happened to me as well though not as severe as your experience.

As the plugs and connectors age and get crud/corrosion in them their resistance goes up, this creates heat which in turn raises the resistance more and so it goes till meltdown.

I've run 100w lamps without issue but you gotta have good plugs and cable.