Why I like my 116

[koan]

The above picture shows the climate control electronics from my wife's Peugeot. I'm not against technology in any way but this does seem a bit of overkill. Stepper motors move some flaps but they still manage to incorporate some good old fashioned push-pull cables to move a couple of others.

The climate control has played up for years, occasionally but becoming more frequent if the knob was turned to warm and then back to cool the system would stick in heat mode and could only be returned to cool by turning off the ignition and waiting a few minutes. That fixed it most times but recently it was becoming necessary to disconnect the battery to return to cooling.

I was out in it the other day with it stuck in heat and couldn't get it back to cool with the ignition off on trick. Playing with it, winding the knobs backwards and forwards, getting slightly annoyed, it stopped working altogether. The indicator lights went out, the blower came on full followed by smoke from around the knobs.

Pulling the electronics out and powering it up revealed the problem, a hefty sized protection diode pouring out smoke from a crack around it.

Combed the web for a suitable replacement and put it back together, It's all working again and hopefully the sticking heat problem has gone away for good.

The blown diode, none other than a LUCAS part...

koan

[TJ 450]

Ahh, the joys of electronics. That is quite a heavy duty diode... perhaps it requires a higher spec replacement in terms of current rating? That is funny how it was a Lucas part.

Tim

[koan]

Ahh, the joys of electronics. That is quite a heavy duty diode... perhaps it requires a higher spec replacement in terms of current rating? That is funny how it was a Lucas part.

It's two back to back zener diodes in one package connected directly across the 12V supply, that's why it blew the 25A fuse for heating and A/C.

The part number is TP4082, couldn't find a anything about it but I did find TP3082 from Lucas.  Transient protection diodes in that size package are rated for 3 or 5kW surges. I could only find 33V locally in a big size so that's what I used. Would have been happier with something closer to 12V, like a 22V version but none in the country.

We had a bloody good laugh when we found a LUCAS component letting out the smoke

koan

[Mforcer]

I don't understand your specific reference to the Lucas part. Are they renowned for failure?

[goldacre]

I was at my friends place looking at his collection of Rolls Royce cars with the mandatory under bonnet inspection  He talked about all the refinement and detail etc etc etc to which i mentioned 'oh, your car uses Lucas electrics? my Merc has Bosch electrics.' He stopped talking and looked up at me and said, quite simply 'bastard' 

Does he have issues with his Lucas electrics? he sure does! they are in the same boat as Leyland and Rover for reliability, just listen to Clarkson on TopGear when he bags those past car producers 

That said a lot of farmers out my way still drive old Leyland trucks and love them although the engines are from old Holden Kingswoods and what ever else they could cannibalise.

J

[WGB]

No one who grew up with old British Cars could mention Lucas without the mandatory title "Prince of Darkness".

So I have.

Bill

[Big_Richard]

One has clearly never owned a Jag if one knows nothing of Lucas electrical issues

Also,

Those things leak almost as much oil as an unloved w116, when owned by an enthusaist!

[koan]

A web search on Lucas will find plenty of mentions of Lucas parts "letting out the smoke" which was my particular reference.

The most unreliable connector ever was the LUCAR bullet connector.

koan 

[s class]

As electronics students back at university, we used to joke that the way to become millionairs would be to invent a device to reinsert smoke into electronics.  The reasoning is, it stopped working when the smoke came out, so the smoke must be the active ingredient