Hi everyone,
I just finished installing an upgraded Delphi engine wiring harness on my '95 E320 sedan today. It took me two days to do the job since I'm working outside and had to take frequent breaks to come inside until my fingers thawed out. Not a job I recommend in cold outside weather.


There is a very useful video on Youtube where one guy replaces same harness(124 440 5632) on his '94. He mentions that you don't need any special tools for the job,but let me add that there are a few tools that will help make the job easier. They include:
A)12" needle nose pliers with curved tip; handy for removing/installing fuel injector connectors as well as disengaging the wire hold-down clip on the ETA plug (down in the 'hole') They also help when needing additional force removing any connectors that have been on the car since it was built((some are really tight and may come apart as your removing them.


B) a 4" 5mm hex key socket bit and long t-handle 5mm hex key. These are good for breaking loose the 2 recessed bolts in the resonance valve assembly and removing the coil cover plate bolts


C) most of the connectors are easy to access, but when you get around to the very front to do the 3 connectors and ground terminal wire, remove the rubber connector from the vacuum port box. This way you stand less chance of snapping the 4mm plastic vacuum line if its old and brittle. Keeping a roll of 5/32 dorman vacuum tubing handy($6 at your Autozone,ect.)just in case you do break a line.


D) remove the 2 vacuum hoses going to the vacuum port box(make sure to remember which nipple to plug them back in). Remove the 2 10mm bolts securing the vacuum box to completely free it for taking off the 3 old connectors. Pay special attention to each connector as you remove and replace. Make sure to put the top bolt through the ring connector on the new harness before you put the bolt back in. I almost forgot this step! lol.


E) you'll also need a 7mm socket and nut driver for removing/installing the small nut holding the grounding cable to the terminal block mounted on the driver side inner fender panel. Best to remove the 16" weather strip just above the plastic cover over the terminal block so the cover doesn't snag and comes off easier. a small magnet placed on the shaft of the nut driver may help from dropping or losing the nut when removing the grounding cable. Tweezers are handy for removing/replacing the tiny washer that goes back on after you put the cable on.



OK. I think that should do it for tips. After replacing my harness, plugs, wires and COP connectors, the car runs great without the slight misfire I had before starting the job. It even has much smoother shifts. Before it seemed to shift with a slight 'bump'. It's smooth as butter now. Hope these tips can help someone in replacing their harness. Have a great weekend!
Bruce (dcman2003)