Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Rear Fog light

Bob if you need to look further than the rear light connection and fuses then here’s a possible suggestion?

Unfortunately the rear fog light circuit is integrated into the dash pcb. Therefor if you poke one probe of your multimeter into the back of pin 6 (red/yellow wire) on the 12 way Molex connector on your pcb, you should see 12v if all is well when the fog light is activated (attempt at connector pinouts here). This connection runs directly back to the fog light.




NB-Should it be the pcb at fault it’s not that difficult to wire a separate MOT compliant switch.

Have fun….

Just a thought Roger. Are the 4/4 looms and associated components the same as for Plus 4 year on year? I ask because no mention is made of 4/4 on loom schematics covering this period.

I agree where is all the 4/4 information…

My previous 4/4 loom was the same as a +4 of the same age. Oh and my 4/4 dash pcb had a label saying “Module V6” on the back!

I very much suspect there will be some loom difference re the Sigma 4/4 because it has a differnt engine/ECU/MFU... However the dash pcb’s “appear” similar from the images I’ve seen, so most likely share some common functionality at that level.

Are any 2 Morgans ever the same

Thank you Paul. I was hoping for exactly that type of heads up. I have all the parts books on trads. I simply don't post them after 2004. The company began to change their cars so rapidly without notification of what and when, that covering them on them on gomog became an uncertain prospect. Additionally, the number of overseas variants and their distance from UK stock blossomed. And I am not aware that they publish a parts book every year.

So I ended gomog coverage at 2004. Forums are a much better venue to cope with post-2004s.

In this case, began by posting 2004, hoping for a heads-up if wrong (the MMC did now produce a book every year). In fact, I know of no diagram from 1990 to 1998. With the contribution of moggers, I have been trying to cob something up for decades. [/i].

I also have a 2004 "Early Morgans" version, a 2006, a 2014 and a 2016 if needed.

Of course, the wiring for fogs et al did not change that I can see, from 2004 to 2016. But the supplier changed once again. I have found that each supplier is progressively harder for the home hobbyist to read. The 2004 is easier. And the advice here has been excellent on this one.

TY again and keep an eye on me!!!

Lorne

Thanks Roger. I guess the clue is in the dash layout/switches which if the same will have same dash loom at least.

Assuming your dash is the same as Rog's Bob, you will have the PCB controlling rear fog operation. Note for some reason MMC chose to have the rear fog triggered by sidelight operation only. Later models including GDI Plus 4 and 3.7 Roadster used a far more robust essentially sealed BCU to control rear fog light which requires that headlights (dipped or main) be on for rear fog to work. This ties in with other manufacturers as best practice.

As mentioned elsewhere the only MOT requirement is that rear fog works when selected and has warning light.

Well it’s working but why.
Decided to have another look this afternoon. Tried it & still not working. Checked fuse continuity OK. (Again) Replaced fuse still not working so removed fuse & went to check voltage. (again) Now all laugh! set the analog voltmeter to 50mva DC rather than 50 volts DC. I use an analog meter. Yes not looking at what I was doing trying to hurry as I was supposed to be cooking super. At 1st touch meter went hard over. Tried again hard over then nothing. Meter fuse gone I guess when I realised my mistake. Much muttering so replaced fuse & replaced cover & closed bonnet. Thought I’d try the button one last time. B’dy it was working. Having switched the oven on for super, replaced fuse in meter. & cooked super.

Did you see that film gremlins, well they/ it is alive and well in my place.

Well done (eventually). "When all else fails, try reading the instructions".....

A theory: when you applied your voltmeter on the mV range, it would have offered a much lower resistance between the terminal you were testing and earth. That enabled a much larger current to flow, as demonstrated by the meter fuse blowing. But that current also flowed from source (battery) via all the connections up to your point of test. If there was a high resistance connection along that path, the excessive current could have burnt it down to a lower resistance that is now low enough for sufficient current to flow to light the fog light.
So, in essence, if this happens again, you need to focus on the wiring between this test point back to the battery, rather from test point towards the fog light.
Hope this makes some sense.

( For those interested in elektrickery: In my younger days working on the nation’s electricity supply network, underground cable faults were easiest to locate if they were either a dead short or completely open circuit, but anything in between was virtually impossible. One of the old tricks in changing the fault characteristic on high resistance faults was to lash a few electric fire elements to the end of the cable to draw plenty of current to either burn the fault down to a low resistance or blow it off completely. “A sh*t or bust method” Either way, it would then be a doddle to pinpoint using more sophisticated pulse echo equipment.)

Ah yes. My Dad was a radio engineer. IIRC he called it “goosing” the circuit. Hopefully my mistake hasn’t done any damage to the CANBUS. I’ll recheck the bulb connectors & earths again if we get a sunny day. I live by the sea & the car lives outside under a cover which is not ideal. Our idea of building a 2 car garage got scuppered by 2 trees on next doors property with TPOs on them. Annoying as they are only a field maple & a Sycamore.

Dont think canbus was utilised on 2011 models, so should be ok.