Cigarette Lighter Fault

Good afternoon all,

While my car is off the road and Kaz is looking after the A/C CCU, Radio, and Gague Cluster, I have a lot of centre console out. I've hopefully fixed my aspirator fan rattle once and for all (2nd time lucky.)

Before putting the car to bed I'd noticed that everything I put into the cigarette lighter would go pop, quite literally, sometimes with smoke!

The cigarette lighter and ashtray lights (now LED) are happily working and they seem to share the same ground wire. Is there a way that I can test the functionality of the lighter while it is out of the car?

** the only things i could think of were visually inspect, sniff for signs of anything melted and continuity test either side if the circuit. All OK! **

It'd be nice to have cigarette lighter/USB power especially prior to my trip to LeMans this year.

Clean the element/contacts with contact cleaner?

Sounds like a high resistance is making the wrong part hot.

I had a car (MX-5, I think) that would fire the fag lighter like a missile, which was scary. Had to bend the clamp tabs in a bit.

Not exactly sure what 'pop' means. Do you mean that you are getting a short circuit with sparks and smoke? A short to ground would normally pop the cigarette lighter fuse which you have not reported.

The cigarette lighter is on a separate supply from the ashtray and cigarette lighter lights; but, they do share a common ground. The cigarette lighter does have its own fuse (#15) so if you were shorting something I would expect that the fuse should be blowing. The cigarette lighter also has something called a thermal fuse in the base of the socket. I believe the purpose of the thermo fuse is to protect from overheating if the actual cigarette lighter fails to eject once it reaches operating temperature.

The normal practise is that the metal shell of the cigarette lighter is negative and the center pin is positive. This is a photo - not my NSX
Attachment 14737

In other cars, the thermo fuse is typically connected to the center (+) terminal. The Electrical Trouble Shooting manual implies that the thermo fuse is connected on the ground side which is odd considering the diagram in the service manual. Regardless, given that you have not reported fuse popping I expect that what may be happening is that the center contact in the actual socket may be coming loose and moving around when you insert 'whatever' or the connection of the socket to the thermo fuse case may have come loose with the same effect resulting in an intermittent connection and possible sparking at the bad connection point location. If the center pin in the actual lighter socket has come loose, I don't know whether that is fixable. You may need a new socket. If the thermo fuse case has come loose I think that may be fixable.

I have attached the section from the service manual describing removal and separation of the lighter parts. Once separated, I think the problem and the repair options should be apparent.

Attachment 14738

if you need the cig lighter i have an unused new one available

PM if still required

Thank you Old Guy for the info and Nobby for the offer. Nick, I'd definetely pass on a flaming hot missile!

Kaz, as ever, kindly passed on his knowledge of the system in a recent Blog post for which I am very grateful. I disassembled the unit and found it to be fine visibly and working again with the cigarette lighter on re-assembly. The cause of my woe is the compatibility issue between our cigarette lighter socket and modern power adapters. I'll refrain from using power adapters and have instead used a fuse adapter to power a USB lead in the glovebox and arm rest