Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Flashing heated screen switch

That PCB seems to be an integral part of switch complete with lead and plug as shown here with matching rear fog switch.



Although this pic is from a Roadster it seems if the positioning is similar it could explain why your rear fog switch was affected on initial issue. Given the huge price of replacement and if only the PCB is affected it seems a home spun solution wouldn't be that difficult. On close inspection the PCB carries the LED illumination and a resistor to give the dimmer illumination. Even a bodge salvaging the working parts of an old switch would likely be more rugged than OE.

Richard I am on my second PCB. They are cheaply built and wat too complex. I love to find someone who can build a simpler solution, by passing as much from the board as possible.

When you say PCB John do you mean the whole switch with lead and plug or literally just the PCB part which would require a fair amount of re-soldering into postion? The parts book suggests just the complete switch is available, no individual parts.

Would be happy to investigate a replaced one if its deemed U/S, as I'm sure some parts would be salvageable.

ETA: my comments referred to the momentary switch type used to control front/rear fog lamps, heated screens and possibly air con., where they just offer a toggle on/off signal to the BCU, and introduced to Roadster and +4 models in 2014. I'm sure the PCB's on earlier types could be bypassed similarly though.

Richard, my understanding is it is the PCB. Bear in mind it is an older version than yours. Graham has had a look but couldn't solve it due to the useless new circuit diagrams.
If you want a go let me know.

Rear fog lights have a PCB to manage when they come on and cancel.
It was introduced some years back to prevent people leaving the fog lights on. They should only be able to be switched on when dipped headlights are used and switching dip off resets the rear fogs to off and they then need the switch activated next time you want them on. A bit of a logic circuit to prevent them staying on.
I had issues with mine (2002 Plus8). I narrowed a problem back to the PCB. It was loose inside the black plastic box screwed to the frame. re glued and ok for a while. It started again. Struggled to get a replacement ( sent photos to Melvyn ) after 4 months of no replacement coming from the factory I had another look. Spotted a couple of iffy solder joints. Renewed them and problem has gone.
It’s a shame that people with the skills to work on simple ( relatively) circuits are disappearing.
Have a look at your PCB’s to see if you can spot anything like loose joints, corrosion, burn marks etc. Just take care when handling them in case you short circuit across components.

OK that explains the situation better thanks John and sospan. I did edit my post to say I was referring to the 2014 onwards version (as illustrated) which uses external BCU control for timing of heated windscreen and headlamp state to control fog lights. It seems I made a false assumption the OP had this type since his was a 2014 car Apologies for confusion.

Richard, they keep changing the design. For sure the 2014 will be different to mine.

Given the horrendous cost and fragility of this PCB (not to mention availability) it seems an entirely separate and far cheaper solution would be appropriate. For the heated windscreen something like this latching relay with built in (adjustable) timer would provide an all in one answer.



This particular one requires a momentary input before timed period is started, and the 10 amp contact rating may be a bit marginal but I'm sure there are more suitable ones to be found, or use of an extra relay.

Regarding the rear (and front if fitted) fog light(s), a relay triggered from headlight switch or dipped beam only would solve the problem simply and ruggedly for a small fraction of the PCB price.

Warning light intensity could be wired to suit with suitable resistor in both cases.

Richard,
sadly electronics is not my strength. I would need someone to do that for me.
John