Removing the 30-pin connectors from the ECM ?

Iceni John · November 05, 2015, 10:33:39 AM

How do you remove the two big 30-pin connectors from a DDEC II ECM? Each connector has a 1/4"-head bolt in the center, but even after I turned those bolts CCW the connectors don't come out of the ECM. The small connectors are easy to remove - just lift their clips and pull their bodies, but the two big connectors are recessed so I can't grasp anything to pull them out. Is the 1/4" bolt supposed to back them out? If so, it isn't working! Obviously I don't want to pry them out by their seals.

What am I doing wrong?! The DDEC II Troubleshooting Manual is silent on this matter!

Thanks, John

stevet903 · November 05, 2015, 11:34:54 AM

That's not good. The connectors should back out when the 1/4 in bolt is unscrewed, and you should be able to pull it off fairly easily once the bolt is released. I have seen the captive nut inside the connector spin, which means that you can't unscrew the bolt and you can't get the connector off. Unfortunately, taking the cover off of the ECM won't work, because the nut is part of the connector and is not accessible from inside either. How bad do you need to take the connector off?

- Steve

Iceni John · November 05, 2015, 11:50:49 AM

I need to remove the Vehicle Interface Harness 30-pin connector (the far one) because I will be soldering some extra wires to the purple, purple/white and pink wires to power a new extra pair of SEL and CEL lamps on my rear start panel. I would prefer to not solder onto wires connected to something electronic - I don't know if my soldering iron could cause harm to the ECM, but I don't want to risk it. Plus, after a quarter-century it may be a good idea to unplug them to clean off any corrosion on their pins!

Darn, nothing's easy.

John

Cary and Don · November 05, 2015, 12:45:53 PM

We had to take those loose also. Had the same problem. Finally just started wiggling them a little and had to pry around the edge a little and they came loose. The next time they just backed out easy.

Don and Cary

stevet903 · November 05, 2015, 01:24:02 PM

You could always get a jumper wire connected to ground with an alligator clip on the end, and clip it to the wire that goes to the ECM while you are soldering. If there is an issue with the iron, the ground will protect the ECM. (Disconnect the power connector, the top middle one while you are soldering)

jackhanow · November 05, 2015, 01:50:21 PM

maybe you should buy a better iron. i've never been shocked or eletricuted by one. the power doesn't pass through the tip or else you would get zapped as soon as you touch the solder to the tip.

Iceni John · November 05, 2015, 02:59:28 PM

Problem solved!!!

Guess what?? I was using a 1/4" socket, but couldn't understand why the darn bolt wasn't turning. It was an 8-point socket! I've never seen an 8-point before, and I had just assumed it was a 12-point. That's why it looked so much larger than the 7/32" 6-point! So, now I know, don't assume anything. I turned the bolt slightly with a wrench, and the connector is now slightly loose, so all's OK, I hope. I'll buy myself a set of proper 1/4"-drive sockets, then I'm good to go.

As for not soldering on circuits, I was once told by an instrument technician when I worked offshore that it's just poor practice to do so in case any stray voltage leaks through. I would hate to zap my ECM for that reason. Heck, some circuit boards come packed in anti-static bags and have warnings to make sure there can't be any static from you or anything else, so maybe a DDEC is equally sensitive? Better safe than sorry (really, really sorry). I used to have an old Weller soldering gun that gave me tingles, so I junked that and bought another - who knows if it was leaking stray voltage onto whatever I was soldering?

Thanks for all the good advice (as always).
John