'00 headlight connector melted.

Hi All, I'm having a problem with one of the headlights in my '00 S40. The bulb went and when I was replacing it I noticed the common wire and the plastic around it on the connector was partially melted. The replacement bulb didn't work. I checked the fuse and it's fine. I'll have a look later on today to see if the melted plastic was causing some kind of obstruction to the connector but in the meantime has anyone seen anything like this before? Where else should I be looking for problems? Thanks, Colm.

If you have a volt meter confirm current is getting to the actual bulb holder....you can then establish if its the unit or wiring prior to...

there is a high probability that what you have there is a high resistance joint(resistance=heat especially when dealing with that amount of current that is running through those connectors) What this means is there is a bad connection which needs to be sorted or it will just carry on cooking until it fails(sounds like this has already happened) A poor contact can be caused by many different things but it is normally dirty contacts or not enough surface area on the contact points. Make sure all the contacts are clean and that they are nice and tight.

Thanks for the quick replies. I'll check the voltage at the connector and see that at least power is getting to it. Assuming that this was caused by some obstruction on the connector I'll have to replace/refurb the melted connector before I can hope to solve the problem. The next questions is where do I look for a replacement connector? I'm sure the main dealer will want to replace the entire head lamp assembly. I know I could just directly connect the spade connectors to the back of the bulb but that would just irritate me every time I saw it... Colm.

You're right it's not like I'd look at it every day but I'd know it was there.... Maybe when I try to buy the connector I'll ask my local Volvo dealer to sell me a book on how to stop being so fussy and just live with it :) Colm.

This light is officially a head wrecker... 

Lamp earth lead 

Problem will be the earth lead from the bulb connector to chassis. This is what melted the connector body in the first place. Correct input voltages are present according to previous posts, but the earth path from lamp to chassis is high ressistance, blocking current. Did you just replace connector housing, or connector and harness back to main wiring harness? With a multimeter, measure the resistance from the bulb earth terminal contact in connector back to the battery negative terminal (bulb disconnected). This must be less than 0.1 ohm resistance as it carries at least 5 Amps when H/L is on. If you only have a voltmeter, connect the bulb into circuit and measure voltage from bulb earth terminal to battery negative terminal with H/L on. Must be no more than .25v, but start test with meter on 12- 20 Volt range and step down ranges if reading indicates safe to do so.

I only replaced the connector. It doesn't matter too much now but here's a picture of the burnt out connector: Where is the earth connection on the bulb connector? I presume it's somewhere around where the bulb fits into the back of the headlight assembly. Would there not be a common earth path for both the parking bulb and the dipped/full headlight? The parking bulb is working correctly. Thanks, Colm.