Got a 480, but the CEM is being shy (CEM location, turn indicators)

[IKnowItsABadIdea]

For those that might remember my first thread where I looked for a 480 with air con - well, I got one now. A 1988 480 Turbo! So expect to see many more posts I guess

The first order of things to fix is the indicators, they are all dead (left, right, hazards and both on the dash and all external). Since the car was inspected and deemed road legal as recently as this summer, it can't really be all the bulbs failing since then. And since I also hear the periodic clicking I know the relay is going. It shouldn't be able to be the fuse, but I checked it anyway and it's okay. With this information, a look at the schematic pinpoints this to either the relay in the CEM not making contact when closed, some soldering issue related to that signal or wring at CEM output B4.





So now all I need to do is to grab the CEM and have a look inside (unless the wiring to it is obviously bad). So where is it then? The FAQ on this amazing website is pretty clear:



I also found an image on a French forum that seems to agree:



However, my CEM doesn't seem to be accessible behind this cover. However, I do see the edge of some electronics box that seems very hard to get to. Is this my CEM? Is it supposed to be up there? Can I get to it without removing the entire dashboard? It was held on by a single screw in the lower right corner and I removed that one and tried to wiggle the CEM out, but it hits the edge of the dash. I would like to avoid breaking something on my first job

It also seem to have a different connector from the one I posted in picture 2, does anyone have a pinout for that?

[jifflemon]

Yes, thats the CEM up there!. So, first of all remove the bonnet release mounting bracket too. Should give a little more wiggle room.

On RHD cars, removing the glove box gives a little more access to get to the screws; You could possibly try removing the dash cluster (because, lets face it, it'll probably have to come out at some point!) to give you more room?

If you've got the power connectors (B+C) at the top of the CEM, you've got an early one. There's a bloke in the UK who may be able to help out, but it may be worth looking for Euro contacts first.

[jifflemon]

Just another thought....

You may get more access by removing the cover and screws from the relay box under the engine and pushing it inside the car. You may then be able to reach the CEM by going through the engine side (as crazy as it sounds!)

[IKnowItsABadIdea]

Okay so I can confirm that I have the other connectors at the top and that makes it hard to wiggle out.

I tried to remove this panel, but it didn't came out even when pulling somewhat hard. It just flexed in a precarious way. Is there a trick to removing it safely?



My hope is to be able to unplug the upper connectors via this panel, then rotate the CEM 90 degrees and pull it out downwards (after removing the bonnet release mechanism as suggested by jifflemon).

[jifflemon]

Removing that side part won't give access - You could loosen the dashboard mounting bolts there to give the dashboard some "wiggle room"

Have you tried going in from the engine bay side as I suggested earlier?

[Keyz]

It might just be the turn signal relay that is corroded or stuck...

[jifflemon]

It might just be the turn signal relay that is corroded or stuck...

The turn signal doesn't have a relay - it's part of the CEM

[IKnowItsABadIdea]

So I got the CEM out, the trick seemed to be: put on a head lamp, lay half upside down and put your noggin in the foot well so you can see what you're doing. You'll then see that there is an air vent under the steering wheel that looks like it's blocking the CEM from rotating clock wise, but with enough persuasion it's actually possible to get it past that. Once rotated the top connectors can just be pulled out (no lock for those).



The copper braid that joins the relay frame to the contactor (or what the proper terminology would be) seems to be a bit burnt/darkened. But I could load it with 3 Amp and it dropped "only" 0.5 Volt. That's a bit high, but shouldn't be more than 1.5 V when driving the indicators and that should just work fine. Since I can also hear the relay clicking, the fault might not be in the CEM for me. Or the problem was the contacts that I have now cleaned.

[Alan 480]

Maybe even the act of unplugging the main CEM will have be sufficient?

As a wee hint , disconnect the main battery BEFORE plugging the CEM back in, I have no idea why but when plugging back in again the ruddy starter would spin over!!! this happened a few times as well

I'd had issues with the windscreen wipers, solved by swapping the switch gear AFTER I'd pulled the CEM

[Keyz]

It might just be the turn signal relay that is corroded or stuck...

The turn signal doesn't have a relay - it's part of the CEM

Yes, I know. That's what I wanted to say, the turn signal relay inside the CEM. Some folks just solder an other relay.

[Keyz]

So I got the CEM out, the trick seemed to be: put on a head lamp, lay half upside down and put your noggin in the foot well so you can see what you're doing. You'll then see that there is an air vent under the steering wheel that looks like it's blocking the CEM from rotating clock wise, but with enough persuasion it's actually possible to get it past that. Once rotated the top connectors can just be pulled out (no lock for those).



The copper braid that joins the relay frame to the contactor (or what the proper terminology would be) seems to be a bit burnt/darkened. But I could load it with 3 Amp and it dropped "only" 0.5 Volt. That's a bit high, but shouldn't be more than 1.5 V when driving the indicators and that should just work fine. Since I can also hear the relay clicking, the fault might not be in the CEM for me. Or the problem was the contacts that I have now cleaned.

If copper is burnt/darkened, there's more resistance. Relay can click but if the controlled wire (12V) will not have enough power to feed the corner lights.
A clicking relay, doesn't mean a working relay...