Dramatherapist

Dramatherapist

Member
Hi, a couple of weeks ago in the heat and acrid smell came from front of my car. Stopped, checked under bonnet yep something had melted. I have later discovered it was my aircon loom. Nothing else appears affected. Two things, what may have caused this and secondly is it a matter of cutting out the melt and splicing in new wire, or better to replace the whole loom. There appears to be multiple plugs on the loom in online pictures. Any help appreciated, cheers. Perhaps I will add pics when we get the warm days arrive to show extent of damage.
 
Oh should also highlight the Aircon had been on for a few hours on a very hot day. There was no other effect noted than the absence of cold air from vents and the smell to smoke or flame noted.
 
Can you post pictures of the issue, as the AC wiring is spread all about the engine bay. I can't work out how it can melt, as the AC circuit only has a small capacity fuse.
 
Screenshot_2025-07-20-12-46-55-47_260528048de7f2f358f0056f785be619.jpg
 
Thank you. If rain stops today I'll look. I will start from pump and work backwards. Expect one core goes to fuse other towards bulkhead to switch. Assume it's a simple push to make loop.
 
Dramatherapist said:
Thank you. If rain stops today I'll look. I will start from pump and work backwards. Expect one core goes to fuse other towards bulkhead to switch. Assume it's a simple push to make loop.
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AC is more complicated than that.
The ECM controls the AC, depending on the position of switches, and various factors like AC gas pressure, evaporator temperature, engine load, and system voltage. The ECM also controls the cooling fans, as those must run for AC to work correctly. Like I said, it's unusual for the wiring to cause issues, as it's not under large electrical loads, although it's possible to get damaged, like any wiring can. I've come across a damaged AC clutch coil before now, but that should blow a fuse, rather than melt wiring.
 
Thank you. If rain stops today I'll look. I will start from pump and work backwards. Expect one core goes to fuse other towards bulkhead to switch. Assume it's a simple push to make lop
 
How long have you owned the car?

I'd check your fusebox and make sure someone hasn't replaced a (something like) 5amp fuse with (something like) a 50amp one!

All wiring is rated well above the fuses, so should not burn out.
 
This car 125,000 miles, and £800 in good condition with 4x4 full service history. I will check fuses and wire in my assessment. The acrid smell reminded me of a friends herald where low amped wire caused some issues during a rally.
 
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