Do all xj wiper motors have this problem?

My wiper motor was getting pretty slow...no high speed, and lagging low so I swapped in one from the JY a year or so ago. It worked fine on normal speed, but it too had a high wiper speed that was barely past normal wipe mode. So yesterday I finally decided to order one from the parts store and today when I put it in I was a little ticked to find out it performed the same...fine on everything but no high speed. Do all XJ wipers motors have this issue with the High wiper setting? Or am I just getting a string of poor performers? Ive also changed out the little black box that controls the intermittent wipe mode just in case but that did nothing either.

Thanks,

Me

I have a slow or inoperative rear wiper but I believe it is due to a wiring issue, and not the motor. I can see a break in the wire when I open the hatch and look at the exposed harness.

I didnt notice any cracks in the wiring, and even if there were it still wouldnt explain why one of the motors halfway worked on high and the others didnt speed up at all...its making me with I would have just kept the old one that half @ssed it lol.

There is a black box attached under the driver's side dash with velcro that is a solid state speed timer that is easy to swap (get one at a JY), and is probably the problem. Opps, I see you changed it, are you sure that one is OK? Other possible issue is a bad ground. What year is yours?

Mine is on the same circuit as all sorts of other stuff, and is way overloaded and tends to burn up the wires and the ignition switch way too often. I finally by passed the ignition switch on my 85 and 87 for thatr wire, went from the BS 12-14 ga wires and 25 amp fuse, to 10 ga, and 30 amp dash switch and fuse on mine. My 87 has the AC blower, wipers, e-windows, ass wipe, and about 6 other things, radio, turn signals.... all on the same damn wire!!!!

Since you tried a new one, it must be the wiring, hot at the switch (like mine was), and or a bad gound path for the wiper.

The steering column selector could be bad too I guess, but from the sound of it I would check the ground and brown wire at the ignition switch for damage from overheating.

As far as I know high and low speeds are fed from different wires, so if you're getting both speeds the problem is not likely to be in the controls or the wiring. However, if the wiper linkage is very stiff or binding, it will slow the motor down, as will a bad or dry bearing in the motor itself. I had this problem on one of my Jeeps where the bearing got progressively worse, and it showed up first as a slow high speed. I think the first thing to do, assuming that you have a new motor, is to unhook it from the linkage and see if you can perceive a difference in speed. If the motor works properly, then check the linkage, and remember too that it will be slower on a dry windshield, so test it with the wipers lifted, or in the rain.

As for rocknxj's rear wiper, while wiring may well be at fault, it would be a good idea to make sure the output shaft isn't binding, and to do it before it stalls. If it binds enough to stop the motor it will either burn out or strip the gears. If you catch it in time you might be able to get enough lube into it to save it.

At some point, not sure quite when, they changed the design of the rear wiper motor, and made it non-serviceable. If it's an older one you can take it apart, push out the output shaft and lube it properly. If it's a newer one you'll have to try to work something in, or grind/drill/mill the rivets out of the motor, and replace them later with small machine screws.

Good point, so I would add a poor ground to make two possible issues.

The connectors going into the black box will plug into each other without the black box....mine was doing the same thing and I bypassed it by just plugging them into each other....try that just in case your new black box is bad too....

bigdummy30 said:

The connectors going into the black box will plug into each other without the black box....mine was doing the same thing and I bypassed it by just plugging them into each other....try that just in case your new black box is bad too....

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I forgot about that trick!!!!

will give it all a try tomorrow. I did check out the speeds with the motor out of the cowl. The old one only showed a slight increase in speed. The new one shows no increase at all. Will work on it some more tomorrow and let you know what I find.

Thanks for all your help

Me

You might do well to check voltage at the plug for the motor. Terminals 5 and 6 on later models (at least on 95-99) are the + for the two speeds. 4 is ground, 1 & 2 are the park circuit. Make sure the ground is good, and then check voltage at 5 and 6 with the switch turned to low and high. You should get 12 volts between ground and the chosen speed, and nothing between ground and the speed not chosen. If it's working right at the connector, then I think the motor is bad.

Matthew Currie said:

You might do well to check voltage at the plug for the motor. Terminals 5 and 6 on later models (at least on 95-99) are the + for the two speeds. 4 is ground, 1 & 2 are the park circuit. Make sure the ground is good, and then check voltage at 5 and 6 with the switch turned to low and high. You should get 12 volts between ground and the chosen speed, and nothing between ground and the speed not chosen. If it's working right at the connector, then I think the motor is bad.

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Hmm, do you know how the speed is controlled on these? Is it internal to the motor windings, selecting different input wires going into the motor, or done by lowering the voltage or using some sort of solid state pulse width modulation?

Ecomike said:

Hmm, do you know how the speed is controlled on these? Is it internal to the motor windings, selecting different input wires going into the motor, or done by lowering the voltage or using some sort of solid state pulse width modulation?

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It's a two speed motor. The switch simply selects which of the connections gets 12 volts.

mine has had this problem forever too. i always think the low is too low and the high is what the low should be... both speeds seem to get a little faster if the motor has been running for an hour or so but maybe it is just me thinking that it is better...