Thread: Main harness to chassis harness, connectors C0390 and C0376

I had an ongoing problem with a park brake fault caused by a broken and corroded wire in the C0376 connector (you can read my other post) and want to share some information regarding the dismantling and repair of these connectors, which according to the ERL are NOT serviceable.

According to my manual on the Discovery 4 these connectors carry wires associated with the following systems.

Park Brake Module
Fuel Tank QTY and pump
Rear brake wear
Suspension air compressor temp sensor
Suspension height sensors and rear control valve
Rear diff lock if fitted

The Main harness to chassis harness, connectors C0390 and C0376, are due to their location in the hostile environment under the rear LH side of the vehicle, prone to water ingress and corrosion in the wires. Forum users on Aulro and other forums and around the world have reported problems arising in this area from beach driving and washing their cars. I must report that despite the corroded wire I found my connector was completely moisture free and it appeared well sealed.
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The male C0376 connector is in an awkward position with poor access. To work on it to disconnect it , remove the grommet in the rear quarter and pull the loom up into the cargo area. You don’t have much choice with the female connector C0390 but to work on it under the car, though access is not bad considering its location.

I found my broken wire was really close to the backshell of the plug, my biggest issue was finding out how to dismantle the connector to repair it, as the break was far too close to connector to fit a splice. I needed to remove the pin in question and solder a new wire onto it. In the ideal world it would be better to crimp on a new pin.

I was very wary of forcing the connector apart because if I broke it I would be in the **** as so many important circuits go through it, the car would probably not be driveable. After a lot of internet trawling I found the manual for the build up and strip down of this type of connector. They are made by TE and can be found using this link https://www.te.com/usa-en/product-1438842-1.html, Scroll to the bottom of the page for the instruction sheets, remember the ERL says they are not serviceable.

The connectors can be stripped down with simple tools; a small screwdriver to pry off the backshell and displace the seal
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and a pliers to pull out the red locking plate (male connector) the red and white plates can be pulled out at the same time,
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once the plate is out the pins are released by gently bending down the front locking tab, again with the screwdriver, while simultaneously pulling the pin out from the back.
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TE’s instructions are very comprehensive. Assembly is the reverse of removal.
Thanks for reading, hope this helps.

Originally Posted by Jetfixeruk

Hi Bots,

If you drop your spare wheel out and get under the back of the car (support it with stands of course, that air suspension scares me!). You should see the connectors just as they appear in drawing in my post. Unplugging them is a little tricky there is a lever mechanism to lift up to part the plugs, they can be a bit stiff after being mounted under the vehicle for years. There is a splash guard on the wheel arch side which for better access folds down after prising out two little clips. The TE instructions illustrate the lever lock very well.

Cheers Jet, your hard work will help me a lot. Greatly appreciated 👍