Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing 2008 Plus 4 flickering immobiliser light

On the way home from work last night I noticed my immobiliser light was on. The car was going just fine!! A little observation, while keeping half an eye on the road, revealed that it isn't on permanently, it flickers with the "undulations" of the local roads. With the ignition off it flashes in the appropriate manner. The car starts and runs just fine.

I had a similar issue with the ignition warning light a couple of years ago which, in the end, turned out to be a loose signal lead on the speedometer (isn't Morgan electrics wonderful!!). I found that by driving around with the plastic cover removed and feeling around behind the dash till it stopped; I couldn't get it to do it when the car was stationary. My suspicion is that this is something similar, after 36,000 miles of "undulating" road surface some waving wire somewhere is just screaming to be let off.

I found a "harness diagram" on gomog, but it has no sign of an immobiliser or warning light on it.

Does anyone have any idea where to start? Or a "traditional" wiring diagram with everything on it.

Won't it come straight from the ECU?

Good point. But this feels like a return or earth issue.

I have the plastic cover off.

There are 2 large multiplugs on the back of the centre panel, Both firmly enough attached. Poking at their wires produced no change, but a finger under the cover behind the light and just below the rear light push button has changed the ebhaviour. Yes, the light is now permanently on.

I need to take the dash off to do any more, an as I need the car for work tomorrow I am going to leave that for the weekend. I think I know enough to be sure that it's an indicator issue only. Last time I looked at the back of the dash the instruments looked like a sealed unit, but we shall see.

I have once experienced the flickering immobilizer light and a strange coupling between indicator lights and headlights: No turn signals were allowed when headlights were on. The problem was due to water ingress and went away spontaneously once the car was dry.

Harald

No water here!!! and none forecast according to the met office.

Although she did get a bath on Saturday.

I am still confident it's not water.

BTW both front indicators have been replaced owing to water getting in, through the back I think, where it's thrown off the front wheels straight onto a feeble rubber cover. The fibre washer that sits on the spring to hold the contact against the back of the bulb had completely disintegrated and the bulbs were rusted solid into the holders.

Well, after a couple of hours poking about and finding nothing!! Except that the immobiliser light goes out whichever on the multiplugs is removed from the back of the dashboard assembly so signal wire on one and return earth in the other I suspect. The assemby itself comes apart reasonably, once inside it's a single PCB supported on the back of the switches with a ribon cable to the warning light strip. I can no longer recreate the effect with my fingers behind the dash, but I still get a flickering when driving. Moreover, standing on the running board and rocking the car caused the light to go on solidly. So I am wondering if Harald was right and rocking the car like that causes a pool of water in the ECU casing to splash about.

The ECU is in a steel case inside the car attached to the top of the footwell. It's attached by 4 security type hex bolts which I don't have. You can't get to any of it's plugs and pulling the loom about makes no difference. I guess I need to take a trip out and get some tools.

ECU removed from the equation (and the car). The light remained on when the ecu was removed and there was no water to be found.

It looks as though it's a chafing issue at the point the loom goes through the firewall. If I push or pull the loom at that point either side of the firewall I can make the light go on and off.

One of the Emog guys had a similar,though more immediately disabling, issue with an M16 Plus 4 about the time of Mog 2002 in Gaydon, I suppose it is something that will have affected others too.

I am not sure where to go next. Inside it's behind the heater and in the engine compartments it's under the air filter and not exactly easy to get to. I guess I have to take the air filter out and take the loom apart at that point so I can repair the affected wire(s). There is little or no free play to work with possibly as the loom must split just before that to get to the instruments.

If anyone has an easier approach.....

Finally got this fixed. I decided to pay someone rather than doing it myself. The autoelectrician was not impressed. Apparently the bend in the wiring loom as it goes through the firewall is too tight and the loom was pinched when the heater was installed exacerbating the issue. If that is typical then a lot of people have similar issues to look forward to as their mileage increase.

The heater and the ECU had to be removed to get enough play in the loom to examine it thoroughly and fix it, so it's not a small job. He observed that there is plenty of space for a different routing that would not have had any issues.

cost cutting by morgan. less wire,less cost. the mark up on these cars must be way over the top, as I keep hearing of faults from bad workman ship or design on many new cars.

I don't believe it's cost cutting. There is no suggestion that the loom is not long enough or substandard. Rather it's a matter of thinking just that bit more about the impact of a particular installation or component.

This is not helped by the fact that many cars are little used. It took 4 years and 37,000 miles for this to surface and while many cars take 10 or even 20 years to get to that there is unlikely to be a high level of warranty claims resulting and it is easy for the company to not notice the affects. There is no doubt that build quality and material quality has improved enormously from the days when a Morgan could be described as a cheap sports car, however there is still room for improvement.