ABS brake sensor cable - a rapscalion to fix

[sad-lumina-owner]

I mentioned I found a cable dangling in the front passenger wheel-well a while ago that looked like it had been cut.

It is now clear that it is the ABS (auto braking system) signal line and is meant to go to the wheel.

It connects to the sensor mounted on the back of the wheel near the ball joint (tucked up under there...hard to see).

Sure enough the plug was still in the sensor, protecting the contacts from corrosion.

It still looks like it was cut, almost flush with the plug (slight angle, nearly no wire or insulator left on plug), but the corrosion of the wire was too bad to be sure. It also seems to be a weak spot where the cable flexes when you turn left or right (the sensor has to follow the wheel).

I thought this would be relatively easy, reconnecting the plug, so I pulled off the wheel and took out the cable and plug.

The cable runs into the side of the wheel well through a rubber grommet and bracket. On the /94 3.4L v6, this cable ends about 3 inches past the wheel well inside the engine compartment behind the engine on the passenger side, just below the firewall into the cabin.

I removed a plastic clip over the grommet and pulled it out through the wheel well.

Although this is the wrong way to remove the grommet (it is meant to be pulled out via the engine compartment), this actually was a smart thing to do:

This way, the plug inside the engine compartment can be pulled almost through the hole (don't let it slip away back into the engine compartment, or you may have to find it from underneath the car on a hoist).

There was electrical tape wrapped around this plug connection (probably to prevent it from coming undone and being a problem to hook back up...there is no room for hands under the hood).

I tore that off with needlenosed pliers, and used them also to lift the tab to unplug the cable, being careful not to let the socket (also on a cable) fall back through the hole. All this was done from the wheel well.

I carried the cable and broken off plug indoors thinking this would be easy.

I stripped of some 'heat-shrink' (a kind of rubber covering that is shrunk down over a cable using heat).

I stripped a half inch of insulation from each wire (2 wires, one white one black in cable) and the wire looked blackish/blue, with tinges of copper.

I assumed the wire was corroded, and cut back further and stripped it. SAME COLOR.

It became clear when attempted to clean up the wire and tin the leads with solder. No solder would stick to this wire! Damn!

This wire is some kind of fibre/carbon/copper blend, designed for thousands of flexes in a hostile outdoor environment.

I completely dismantled the broken off plug, being careful to save the two little metal tabs I removed, with the remaining wire bits. This wire was crimped onto the clips that are inserted into the plug (after the wires are fed through the rubber water seal and and plug holes. Then the wire is pulled back through the plug to lock in the tabs.

You have to carefully pull the tabs out the front of the plug (not the back where the wire comes out).

Then I gently put the tiny pieces in a small bench vise and pried open the crimped ends using two small needle-nosed pliers, being careful not to crush the clips or snap off any metal from the crimped ends.

They seem to be plated brass. The copper/fibre wire was corroded, but could be cleaned out with a wire brush. Unlike the wire, the clips can be soldered.

I took some teflon coated insulated silver coated electronic wire I had around and made a new cable extension (two colors to keep the polarity straight).

I had noted which wire was which from the small bit of remaining insulation on the plug (the plug is marked with an "A" on the black wire side, the other wire is white-coated.)

I fed these new wires through the waterseal and plug, and tinned them with electronic solder (flux core). Silver coated wire solders nicely to any connector.

I carefully reinserted the clips into the plug, and reinforced the join between wire and plug with some 'heat shrink' sheath and electrical tape (electrical tape doesn't last long outdoors exposed to vibration and water, so you have to use ducttape too, overtop).

Before splicing the two cables, I slipped some more 'heat shrink' over the main cable, to be pulled down over the join and to stiffen the newly made extension.

I took some standard crimp-style electrical connectors (single wire blade connectors) and crimped one end to the original wire (unsolderable) and the other end I soldered to the new wire.

I tried to shrinkwrap each connection individually but didn't have shrinkwrap small enough, and abandoned that in favour of electrical tape, and covered the join with the larger shrinkwrap sheath previously slipped over the line.

I tested the cable for continuity and shorts, then went back out to install it. I held the dangling plug that barely came through the hole in the wheelwell with needlenose pliers while I plugged in the cable and wrapped it with tape to secure it.

Then I fed the cable back through up to the grommet. This grommet was stuffed back into the hole with the needlenose pliers, but a screwdriver would have been better. What made the whole job easier was a good bright worklight that could be moved around while I worked.

I used a 'tie wrap' to secure the cable as it weaved past the brake hose to the wheel.

I fired up the car and for the first time in five years, the ABS brake light on the dash went out.

The dealer who sold and certified the car told us that it was just wonky from age and not trackable. But I think he just didn't want to spend money on this cable, which was not stocked by CanTire, probably because they don't normally wear out (like brake pads do).

Now the light only comes on when the car is started briefly (I think since the wheels aren't moving, and the ABS is self-testing), then stays off.

Ah!. Another small repair done without spending money and by using my soldering talents.

I don't think the substitute wire will last anywhere as long as the original wire, but I think it should be good for another 5 years, even with crazy steering.

When I get a chance, I'll try and get a spare cable from a wrecker.