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The 40 amp fuse located on the trunk fuse box and controlling the convertible top, on a 2005 xkr, is blowing.
I have unplugged the black/white plug, isolating the pump.
What now?
Has anyone repaired or inspected the brass looking motor for the pump?
How to properly test the motor?
I have measured the resistance between the leads =1,I think it should be lass than .5ohms? The resistance between each of the leads and the pump body,=1, believe this is correct?.
Motor good or bad?
I am going to replace the fuse and activate the switch to see if the back windows lower and to see if the fuse blows, in which case it would indicate a short on the swtch or the line, right?
Has anyone repaired or inspected the brass looking motor for the pump?
How to properly test the motor?
I have measured the resistance between the leads =1,I think it should be lass than .5ohms? The resistance between each of the leads and the pump body,=1, believe this is correct?.
Motor good or bad?
...
With the black & white connector opened, you should see about 0.5 ohms across the two leads, and open-circuit between either lead and the pump body.
Not sure I understand the readings you reported.
If it turns out to be required, yes, you can remove the "bell" casing and access the motor to work on it.
Thank you GUS noted.
Dennis
reviewed the measurements and from lead to lead on the black plug I get 0. From each lead to pump body I get 1. If I understand correctly this means the motor is shorted out.
Operating the switch on the top down side brings on the chime and an attempt to lower the rear windows. Everything stops after that.
Operating the switch on the top up side lowers the door windows and brings on the chime. No movement on the rear windows.
I proceeded to remove the two bolts on the motor bronze housing. The housing seems to be held on by a spring of some sort. I could not remove it completely. I do not want to remove the whole pump if possible. You can partially see the winding, it looks bright orange not burned.
First a caution please. Before going anywhere near the motor with power, please be sure you have replaced the bolts securing the bell casing. (That "spring" you felt in trying to remove it, BTW, was the magnetic field set up by the field magnets attached to the casing.)
You can safely pull the casing off with some effort, but let's defer that for now.
Let's also defer applying power for now.
Sounds like you're using an analog meter. Note that the resistance scales progress right-to-left, not left-to-right and are very non-linear. Zero resistance is on the far right (what I think you're calling "1"). Infinite resistance on the far left. Touch the meter leads together and you should read zero ohms.
Be sure you're clear on reading these scales, and have selected a scale where you can see a resistance as small as 0.5 ohms. A 10-ohm scale would be good if available. Then try the measurements again.
Yes sir. Thank you for the warning.
Bolts back in their original condition. No harm done.
I am surprised no one has gone into the motor online or on the Forum.
By the way do we know what motor this is, specs, made by whom? Bosch?
The scale I am using is a digital one, Cheapo. Forgot the good one at the shop.
The available settings go from 200 to 200k ohms.
I have zeroed the meter in the three smallest settings, 200, 2000 and 20k ohms by touching the leads together. Meter starts at 1 and scrolls down to 0 or 0.00. in every setting.
Red lead at VOhmMA and black lead at COM plug. New battery on the meter.
Measurements between the two pins on the black plug are zero.
From the pins to the pump body they go to a solid one.
checked several times.
On the continuity setting , again start at 1 and goes to 0.00.
I've had the motor open. It's a conventional DC motor with permanent field magnets (no field windings) and carbon-like brushes. Plain vanilla. If it comes to that, you can open yours up and have a look by pulling (pretty hard!) to remove the bell casing.
Sorry, but I'm missing something in your description of readings. I don't understand what a reading of "1" describes. 1 ohm?
With the lowest scale being 200 ohms on your meter, we may not be able to distinguish 0.5 ohms from a true zero. You have access to a meter with better resolution?
Not sure if you have solved the problem yet but when this happened to me the fuse would burn out the moment I hit the switch for the top. I tried replacing fuses a couple of times and they kept burning out. Went through some check that Gus recommended and concluded it was the motor of the pump. Brought it to the dealer and they concurred that the motor was toast. A replacement motor/pump cost $2,000 and luckily this was covered under the warranty that I still had remaining.
I suspect a decent shop that fixes/rebuilds electric motors could have fixed for a couple $hundred which is obviously the way I will go if this ever happens again.
Everything tells me it must be a damaged motor. I am not concerned with the how to repair it replace it part, yet.
It can probably be fixed.
Getting it out of the pump is another matter entirely. My back is already killing me from the odd angle one has to adopt to reach there.
Can it, the motor, be removed without taking the pump out of the car?
What holds the shaft onto the pump?
My fear is for the selenoids and its plugs which seem to be unobtainium and the lines.
I know the pump has two bolts up front and two plastic grommets in the back holding it onto the base.
Dennis, what could be wrong, brushes, burned contact area, does it ride on bearings? the car only has 27,000 miles and the pump appears almost new.
Hey Autobahn--same time frame with my car. It was only 3 years old with 16,000 miles when I bought it back in 2008. In a matter of months I got the leak at the latch resulting in a hose replacement. A short while later the pump motor went south. Not what you would have imagined for a car in the $70K+ price range.
Everything tells me it must be a damaged motor. I am not concerned with the how to repair it replace it part, yet.
It can probably be fixed.
Getting it out of the pump is another matter entirely. My back is already killing me from the odd angle one has to adopt to reach there.
Can it, the motor, be removed without taking the pump out of the car?
What holds the shaft onto the pump?
My fear is for the selenoids and its plugs which seem to be unobtainium and the lines.
I know the pump has two bolts up front and two plastic grommets in the back holding it onto the base.
Dennis, what could be wrong, brushes, burned contact area, does it ride on bearings? the car only has 27,000 miles and the pump appears almost new.
All ideas welcome.
Auto,
If there is something wrong inside the motor, it may be an easy wiring fix. For any such work, you'll want to remove the pump from its mounting. You're right to be concerned about protecting the solenoid connectors, but the pump can be removed safely, if it's done with care.
But let's not go there yet.
Do you have access to a meter where we can reliably distinguish 0.5 ohms from a true zero ohms, across the two pins on the black & white connector? If it really is zero ohms, then we need to get inside the motor.
I don't understand what you meant when describing a reading of "1" on your meter. Describe again please.
Yes I will get the other meter tomorrow and will test on another convertible known good there to get base readings.
No need to rush, we will get to it when we get to it.
After retesting I will remove from the tray and will attempt to remove the motor from pump body without removing the lines if possible. + Pics.
Lets see how far we can get.
I do have my gun ready in case the pump needs to be put down. I've located an affordable replacement pump.
Seismic I hear you, I believe this one is going down the same route. The left a pillar cover is removed, the hose sheathing is all crumbly and the headboard next to the latch is very dirty. Latch and hose replacement could be next.
I remembered that a board member had donated a trashed pump to our Jaguar Science experiments on pressure valves, it was sitting in storage.
Notice the motor is held in place by four Torx 25 bolts.
This is the pump side. Notice the bar where the motor driveshaft locks into. Also there are an internal and external Orings.
Motor side. Notice the notch on tip of drive shaft that engages flat bar on pump side. Also the large external ORing. Greenish oily liquid as lubricant. (Pentosin?)
Last edited by Autobahn kid; 02-07-2015 at 03:39 PM.
I went through this same experience with mine not long ago. Read up on Gus's sight and determined bad pump motor. Contemplated buying a replacement on Ebay, but decided to have Top Hydraulics rebuild mine so I would know that it is reconditioned to "as new". Cost was about the same as what a used one in unknown condition sells for on Ebay and it works like a charm.
02-05-2015, 08:36 AM
40 amp top fuse blowing RESOLVED
