I know, this question again, but it hasn't been asked for a while and I didn't see any solutions, so i was wondering what folks are doing these days to address this? For me the only malfunction that i know of is that the battery will drain after a few weeks of sitting, so whatever is causing that is very slow drag. but i did the right thing and installed a battery disconnect. Seems like the ECM noise is primarily on the initial start up after the disconnect switch was opened. Subsequent start ups when the disconnect was closed already do not seem to trigger the noises. i did have the infamous courtesy/dome lights not turning off but i fixed that by bypassing the Light Module, so that wire is cut and just left there at this point. Could that be the problem?

What are folks doing to fix this these days? Is there a replacement widget or a new wire harness segment available or should i just replace the whole harness? Or does someone work on these and refurbish them? I know John in RI is the Berlinetta expert so i'm hoping he is still around but any and all feedback would be great!

 

I've got to wonder if the ECM is making the weird buzzing/clicking, or if it's the Light Module itself. Both parts are mounted to each other and it would be easy to think the sound is coming from one rather than the other. You didn't mention any problems with the way it runs / drives or and new problems; just weird sounds. In most cases when the ECM was going bad it will 'show up' somewhere. Either the car will act funny when driving, the ECM light will malfunction. On the other hand; Light Modules are known for making weird sounds when there are internal problems with them and they are famous for killing batteries when there is an internal fault. Since you know that your Light Module still has unresolved bugs inside it,......... well, that makes me suspect the Light Module as the part making the buzzing/clicking.

The first thing I'd do would be to remove the lower hush panel, drop the ECM / Light Module, separate them from each other ( but leave them both plugged in ), then run the car for a couple days and see if you can figure out ( BE SURE ) which one of them is making the weird noises. You could also unplug the Light Module entirely for awhile; the car should still Start, Run, and Drive normally ( making no weird buzzing/clicking) but you just will not have any lights at all.

My bet is that it's the Light Module and not the ECM.

 

Thanks sir! Good point, i will confirm that it's the Light Module first. Stay tuned!

 

It's definitely the Light Module - the box with the three plugs in the side and the plastic casing with the various lights labeled. buzzes, snaps, hums, hisses, grinds like me trying to hit 3rd gear. Any help would be great....

 

Since the courtesy light circuit was malfunctioning, which I fixed by bypassing the Light Module and connecting directly to the door jamb switches, and all the rest of the lights are working correctly, I'm thinking it's a good guess that it's the courtesy light relay inside the Light Module that is making all the noise. And since it's bypassed and not doing anything anyway, it shouldn't hurt anything to remove that relay or otherwise cut the power to it and see if that stops the buzzing.

What is the easiest way to cut the power to the courtesy light relay? Does it plug on to the circuit board and can be just pulled off or is there a wire to cut or some other way to remove the power? will this cause something else to break?

Any feedback would be greatly appreciated.

 

Issue resolved (I think). Buzzing was coming from the courtesy light relay from inside the Light Module. There are seven such relays inside the Light Module. They are labeled on the outside of the plastic casing that the ECM also fits into. They just plug into the circuit board and can be disconnected by gently pulling and working them off. They appear to be replaceable - https://www.classicindustries.com/pr...rts/19957.html. I suspect this will also fix my battery drain issue. I do not plan to replace the relay since I already rewired my courtesy light to bypass the Light Module and work directly off the door jamb switches. I don't think the relay is needed for anything else so I will just leave it out.

 

Sorry I didn't see this sooner,..... Yes, the only thing the courtesy relay controls is the courtesy lighting. Nothing else should be impacted by removing just that 1 relay.

 

Thanks John. have you tried a replacement with a new relay like the one i linked to? Did work?