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ABS engages when nearing dead stop, bad hub or wire harness?

R

robinsone

New member
So my ABS has been engaging at times when I come close or near a dead stop for seemingly no reason. I don't get a ABS light of any kind, it will just kick on when I'm about to come to a full stop. Another indicator I've had is that when I start the car cold, the Trac Light will go off for a split second and then disappear. Seems to exclusively happen when I'm starting the car cold and doesn't show up anywhere else.

Wondering if this points to anything in particular. I did replace a rear hub and the rear harness chasing down a ABS light which was telling me a bad rear sensor. Turned out to be the ABS control unit.

I want to know if there is a good testing procedure out there to test the abs sensors in the hub or the wire harness to identify the faulty part.

Any assistance would be appreciated, thanks.
 


I'd first remove all of the connectors at the hub and check out the wires, then dab some electrical grease in there and see what happens.

The best way to test these things is with a live data scanner that can watch each wheel at the same time, likely one wheel is dropping to zero right around 3-5 mph and causing the ABS to come on.
 
I found the culprit, it was a broken abs housing on a hub I had previously installed. I had replaced a hub, due to a supposed bad rear abs sensor. The bad abs sensor turned out to be a faulty abs module. The new hub I installed had a taller abs housing than the OEM version. The taller housing meant that it protruded farther back than the OEM unit. Apparently it cracked perhaps rubbing up against the strut mount, but needless to say the broken housing meant that I was losing continuity to the abs sensor.

When I took it all apart the sensor seemed fine and I was able to glue the housing back on. Not sure how long it will last me, but it is interesting to note the change in housing height and/or depth when looking for a replacement. Since repairing the housing I haven't had the problem come back at all.

Other people might want to check out their sensors or housing moving forward with similar issues.
 
Usually what I do is swap wiring from one side to the other, I have some extra wiring that I made into extensions for this. The idea being if you swap wiring and the code comes back it will be on the opposite side if it's the bearing or same side of it the harness.
 
So my problem came back. While the rear abs housing was broken it turned out to be bad front wiring harnesses. Replaced them both just to be sure, haven't had the problem since. When you take off the old wiring harnesses you can immediately tell a difference as they are much stiffer than the newer harness. If you have an intermittent abs engaging at low speeds suspect bad front wiring harness.
 
robinsone said:
So my problem came back. While the rear abs housing was broken it turned out to be bad front wiring harnesses. Replaced them both just to be sure, haven't had the problem since. When you take off the old wiring harnesses you can immediately tell a difference as they are much stiffer than the newer harness. If you have an intermittent abs engaging at low speeds suspect bad front wiring harness.
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I'm having the exact same problem. I plan on putting in a couple of new harnesses ( I replaced the two front wheel bearings about a year and a half ago with some new AC Delco ones) My question is, where do the two wires on the new harness terminate to? Thanks in advance. also how hard are they to put in? Did you have to remove the front wheels or can I put them up on ramps to do this?
 


The front wire harness follows the control arm and terminates into a larger harness up front. You might be able to get to it by turning the front wheels left and then jack up the drives side, and then turn them right and jack up the pass. side if you plan to do them one side at a time. Doubt ramps would help here.
 
FordMan77 said:
The front wire harness follows the control arm and terminates into a larger harness up front. You might be able to get to it by turning the front wheels left and then jack up the drives side, and then turn them right and jack up the pass. side if you plan to do them one side at a time. Doubt ramps would help here.
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Thanks for the info. I'll be doing this in the near future.
 
If you get the front harnesses, there are 2 of them the shorter driver's side (DS) and the longer passenger side (PS). In theory you really don't need the much longer PS one, but to be safe I'd grab it. I soldered in the new harnesses about 8-10 inches from the DS main harness and about 12 inches from the PS main harness. I wouldn't go all the way back to the main harness. With the car jacked up on one side there is enough space to remove 75-80% of the old harness which I found to be enough and then easy enough to work with a soldering iron to make connections to the new harness.

You will easily be able to tell how inflexible the old harnesses are compared to the new ones. Just be sure to incorporate plenty of slack in the harness when attaching it to the control arm (CA) so any articulation in the CA won't pull at the new harness or connections.

Just do one side at a time, pop the tire off and splash shield it goes quick. You might want to have some extra shrink wrap. Some of the kits just came with clamps and I prefer soldering and shrink wrap and then plenty of electrical tape, and some wire ties to secure any slack near the main harness. Since doing this I haven't had one problem with it.
 
robinsone said:
If you get the front harnesses, there are 2 of them the shorter driver's side (DS) and the longer passenger side (PS). In theory you really don't need the much longer PS one, but to be safe I'd grab it. I soldered in the new harnesses about 8-10 inches from the DS main harness and about 12 inches from the PS main harness. I wouldn't go all the way back to the main harness. With the car jacked up on one side there is enough space to remove 75-80% of the old harness which I found to be enough and then easy enough to work with a soldering iron to make connections to the new harness.

You will easily be able to tell how inflexible the old harnesses are compared to the new ones. Just be sure to incorporate plenty of slack in the harness when attaching it to the control arm (CA) so any articulation in the CA won't pull at the new harness or connections.

Just do one side at a time, pop the tire off and splash shield it goes quick. You might want to have some extra shrink wrap. Some of the kits just came with clamps and I prefer soldering and shrink wrap and then plenty of electrical tape, and some wire ties to secure any slack near the main harness. Since doing this I haven't had one problem with it.
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Thanks for the great tips. This should be easy enough to do.
 
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