Heater Resistor Plug Melting Help!

[simba7]

Hello everyone,

I really need some help on what to do and the cause of this issue.

My heater recently started being intermittant. Sometimes it would come on and sometimes it would not.

I unplugged the resistor plug going into the motor of the fan underneath the passenger footwell and plugged it back in but to no change.

I then spotted that the plug that powers the resistor which comes from the cars electrical system had a purple wire which was out!

So i pushed it back in and it started working. It was extremely hot to the touch which was very odd and worrying.

I then unclipped the whole plug and had a look and 2 crimp slots were burnt!

I have taken photos of the plug and socket.

Below is the front view of the connector.
https://i43.tinypic.com/35am91x.jpg

Side view of the connector
https://i43.tinypic.com/17r2n6.jpg

The other side of the connector
https://i43.tinypic.com/dbjs6h.jpg

The resistor plug socket - Their is whiteness on the plastic.
https://i39.tinypic.com/1h32gi.jpg

I appreciate any help from anyone who may have had this problem before.

I am not sure what has caused it. It may be the resistor but i cant see how that can cause the plug to melt!

Thanks

[longy]

HI mate this is exactly what happend to mine dont know what caused it but i changed the resistor for a new one and its been fine ever since,got a new one off ebay for about £38,hope this helps.

[simba7]

Thanks Longy.

I will change the resistor but I need to change the connector as well now as it is burned and can cause a fire i suppose.

Did you change yours?

Thanks

[longy]

No mate,i just pluged it back in and its been fine mate.I suppose you could cut the the old one off and graft a new one on from scrap yard.

[simba7]

The thing is it still works when plugged in since i found that loose wire.

Im only worried as to why the connector melted.

Scrappies are charging 45 quid for the cable!

[livewire]

hello.
just now fixed this.

as the issue is almost always just burning out the 12v supply (yellow) and 4th fan speed (violet) connections.

this can be fixed by cutting these two wires and joining direct to the fan wires.
i used some connecting blocks (choc blocks) which makes a much better connection than the push in blades used in the connector block.
cut the red wire to the fan from the resistor block, cut the yellow at the connector, join these. (as the connector blocks only act as a joint, the feed wire goes from the fuse direct to the fan)
cut the violet at the plug, cut the black wire from resistor block a few inches up, join the 3 wires, so you have 2 blacks and violet. (you need the black from the resistor unit as it supplys the speed settings)

this way removes the connector from the circuit as it appears that it can not handle the full current (at speed 4) and causes it to overheat.

Also took a current reading (at speed 4) which was 14.5 amps. so why have a 30 amp fuse fitted.? fit a 20 amp i would suggest, it might blow before it starts to melt the connector too much!
mine had only melted the connector at the connection for speed 4, no signs on the supply pin which whould had been passing same current? so at a guess it must be the connector rating must be close to the max so it only takes a bad connection,a few years of oxidation, dirty connection for this to start.

[longy]

hi live wire can you post a pic of what you have done please.
ta.

[davelowe]

I haven't studied the design of the resistor on the Megane.

What I will say, is that on some cars, the resistor heatsink is in the path of the airflow for cooling purposes. If the vent/filter is blocked, it has been known to overheat the resistor assembly.

Therefore, I offer only the humble advice to check the ducting for an underlying problem.

If I'm wrong, someone will no doubt correct me.

[livewire]

hi live wire can you post a pic of what you have done please.
ta.

as requested.
hope it helps others.
saves buying new bits and i think this repair makes it a lot safer.

[longy]

Cheers mate for the pic.

[ajsaville]

Hi livewire great post . That's exactly my problem too been under the dash today and renault would like 60 quid for a replacement part with modded cables so they no there is a problem with this wiring loom.

[simba7]

Hi Guys,

Sorry to be a year late, For some reason i do not get a notification.
I thought i would come back and inform everyone that we fixed the issue ourselves.

We bought a scrap connector from Renault and also a block connector from ebay and literally spliced and screwed the wires into the block.

It now has been running perfectly fine.

Thanks for your help guys.

[johnna]

This is my next job. One of many jobs on my crappy car...

I'll post updates as I go on.

[ozi05]

Anyone know where i can get the 2 wire red and black wiring loom for the heater resistor? The one with the small green plug that goes into the heater resistor?

[livewire]

breakers yard? ebay?
a picture would help.
as don't know what wires you mean?