HELP!

The windshield wiper motor or mechanism on my '05 DB9 with 23K mi, seems to be rotating in the wrong direction (turning wipers downward). This occurred after I had the windshield replaced. I re-installed the windshield wiper arms in their original, parked position then turned the wiper motor on and (rather than sweeping across the windshield) they just pressed downward and stopped. I immediately turned off the motor, removed the wiper arms and took it to the dealer.

The service advisor suggested that the wiper motor may either be upside down or backwards! How could that be? They quoted $2700 labor to fix the problem because the engine has to be removed to access the wiper motor.

Unfortunately, I never tested the wipers beforehand and don't have previous owner contact info or history BUT I'm having a hard time believing that the wiper motor could actually be BACKWARDS in the car. The wiring looks perfect and the wiper arms were parked correctly before I took them off to replace the windshield.

Is there anything else I could check? I hate to perform major surgery before getting a 2nd opinion.

Thanks in advance for any suggestions.

Steve

 

If you didn't replace the wiper motor then I do not think this being in backwards or wrong explains the behavior.

If you had to disconnect the wiper motor wiring to install the windshield I doubt you could reconnect the wiring in such a way to cause the wiper motor to work the other direction. But check the wiring connection.

What I suspect happened is you removed the wipers with the wipers in their down position.

You installed the new wipers with their shafts if not in the fully up position but not in the down position either. One can see this happen with the wipers active and then turning off the key. The wipers stop mid-sweep.

Remove the wipers. Activate the wiper motor then shut it off. You want to observe the shafts to which the wipers fit on return to their proper resting position.

Then you can install the wiper arms and test their action.

 

May I ask if anyone has removed the wiper motor assembly? It appears I need to re-clock the linkage to solve the mysterious wiper problem. The dealer says that the intake manifold and possibly the master cylinder needs to be removed to access this area. Another forum suggests engine removal (or lowering). Another suggests a special tool does the job with engine left alone. But no specifics. Thanks in advance!

 

Well, I'll try again. Maybe I didn't make myself clear the first time.

Engine removals are rare and for this car with around 24K miles I would have to say very unlikely.

So, this makes the odds the engine was removed and the wiper motor for some reason removed and then installed backwards or upside down or incorrectly connected to the wiring harness very very remote.

Furthermore, my (admittedly limited) experience with wiper motors is they simply can't be installed any old way but one way.

So I really do not believe the wiper motor is installed incorrectly.

What I believe happened is the wipers were stopped mid-sweep by turning off the key and then the wiper arms removed. When wiper arms were installed again they were installed in the down position. However, the shafts were not rotated to the fully down position but in mid-sweep.

When the key was turned on the wiper motor attempted to complete its sweep and was unable to because the wipers were installed incorrectly.

You were right in turning off the wipers.

Before you remove the engine, or the intake, or anything major, I would advise you to remove the wiper arms, then turn the key on and and activate the wipers via the wiper stalk then turn the wipers off with the stalk then turn off the key.

This should have the wiper shafts at their most down position. Then you can install the wiper arm in its most down position and when you turn the wipers on the wiper should start out from its down position and sweep across the glass to its fullest travel then return and repeat.

There is one other possible explanation. If one or both wiper shafts are driven by the wiper motor indirectly through some linkage and if this linkage was removed then reinstalled for the windshield job it might have been installed incorrectly so the action is reversed.

You or a helper might be able to see this by with the wiper arms removed and with the wiper motor turned on watching the wiper shafts that they rotate the right direction. Put a dab of white paint on the top of each shaft at say 3 o'clock. When the wiper motor is turned and the shafts begin their cycling the dot should sweep clockwise then stop and reveres direction and then return to their starting point and repeat this for as long as the wiper is left on.

Another possible explanation is the wipers were installed in the down position but the wiper shafts were not in the down position. When the wiper motor was then turned on the jam the wiper arms represented caused the wiper motor shaft to spin or twist in the linkage and now this linkage is out of phase with the motor.

In this case the wiper motor and linkage will have to uncoupled and the phasing corrected and then re-coupled. It is possible this twisting or spinning may have stripped motor shaft and linkage drive so one or both of these may have to be repaired (or replaced).

I am not familiar with the Aston Martin but I would guess looking at the car from the front, the wiper shafts should rotate 90 or so degrees counter-clockwise then return. If the shafts rotate in the opposite direction unless the wiper linkage is quite different from what I imagine it should be this is a sign the linkage has been installed incorrectly and is I guess the best I could describe it is causing the shafts to rotate in the wrong direction.

Were I in your shoes I would do what I could to confirm the problem is not just a wrong installation of the wiper arms or a wrong installation or connection of the wiper motor to the wiper shafts drive linkage.

I tried to find a diagram of the Aston Martin DB9 wiper assembly online. I found a web site that I think might show one: www.astonmartincarparts.com; but before it will let me view the diagrams it requires I register and I do not want to do that. Since you own the car you would be the person to register at this site to view the hardware and see if you can spot what's amiss.

I did view a picture of the assembly, not a very good picture, and I have no real frame of reference of how the assembly actually fits, but it is a complicated assembly, at least to me eyes. Thus I would be more in favor of the assembly just getting out of whack, so to speak, from a partially botched windshield installation.

 

Thank you!


Clearly the linkage is out of phase with the motor. When the wiper motor is turned on with the arms removed, the shafts rotate incorrectly which confirms the wiper motor shaft has spun or twisted in the linkage.

It is certainly possible that the motor shaft and linkage drive are stripped and may have to be repaired, re-clocked or replaced.


No way of knowing how bad it is - until I remove the intake manifold and master cylinder to access this area to see what's causing this phenomenon. Gaskets and injector "O" rings are nearly $1000 and 10 hours work. Bummer! Any idea what the "special tool" is that the dealer uses to install the manifold?

 

Sorry, but I have no idea of what tools are required to remove/install the intake manifold on a Aston Martin.

Before you start wrenching on this you must be sure of your diagnosis.

I am not familiar with the hardware on the AM but generally the wiper drive hardware with which I am somewhat familiar is pretty robust, robust enough that if one tried to strip a shaft or force the mechanism out of phase a wiper arm would bend like a pretzel or snap in two before something would strip.

Is there any special steps required to replace wiper arms/blades? Is there some "wiper service position" that is utilized? I'm thinking if there is and this wasn't used to position the wiper and wiper drive hardware for wiper arm removal or wiper arm installation that the out of phase condition you believe is present is not due to something mechanical having loosened or slipped but something related to this wiper service position not being used.

 

Thanks so much for your observations. You are correct, there is a "wiper service position" which is set by fiddling with the controls as seen in this youtube video:

Unfortunately, I've tried that - but it only temporarily "parks" the wiper arms in "mid sweep" position (about 12:00) to provide easier access to R&R the wiper blades. Of course, after monkeying around with that, I re-set them back to the correct, downward "parked" position (about 9:00).


Not to belabor the issue but...


If you're looking at the windshield from the front of the car, there are 3 posts that protrude through the cowl from the mechanism and attach to wiper arm assembly. 2 are "drive posts" and one's just a dead "swivel" post. With the wiper motor turned "off", I have the wiper ARMS installed or "clocked" at about 9:00 which (I believe) is the correct "parked" position. When you turn the wiper motor "on", the mechanism SHOULD only rotate those 2 active drive posts in a clockwise direction, (sweeping the arms across the windshield) from 9:00 to about 1:00, back and forth, etc. However in my situation, from being parked at 9:00, they (first) rotate in the opposite direction (counter clockwise) to about 6:00, then to 12:00, back and forth, etc.


Other observations are that everything operates very smoothly - with no unusual noises - and when the motor is turned off, the arms always park back at 9:00.


The fact that the drive posts rotate in the wrong direction is why the AM service tech believes the drive mechanism is "clocked wrong" or is "misaligned" or "out of sync" and needs to be removed, inspected and re-set - as opposed to it being a computer or electrical issue.


If you have ANY other suggestions that I could try before ripping into this thing, I'd very much enjoy and greatly appreciate hearing it.


Thanks again!


Steve

 

Do you have the DB9 workshop manual? From looking at my copy it's hard to see how things could get turned around or the linkage could get out of phase.

If you don't already have one, go to astonmartintechinfo.com (official AM site) and pay about $100 for a one day subscription to download all the manuals.

 

Well, it reads like the tech has a good idea that the only explanation is something has gotten out of phase, is clocked wrong, or somehow got misaligned.

While I'm generally not in favor of turning a tech loose with what is still a rather vague diagnosis I'm at a loss to explain the behavior.

But before dropping the car off at the dealer along with my wallet, were it my car I might attempt to find a similar car and arrange to observe its wipers' behavior and in fact if possible put the wiper system into service mode and see how the wipers are positioned and how the wipers react coming out of service mode.

Maybe you could find someone in your area with a similar car and a willingness to help you via one of the AM boards/forums?

Regardless, since you are faced with some expense yvr's suggestion regarding the DB9 workshop manual is a good one. I'd spend $100 to download a set of manuals and see if I could learn something from the manuals before spending any more money.

 

Thanks again gentlemen. I do have the manual which calls for the 7 hour job to remove the inlet manifold and master cylinder in order to inspect the mechanism. Gaskets another $500. Although the YouTube vid clearly demo's the "service" and "parked" positions, perhaps seeing it on another 2004 AM DB9 would be the next step.

 

At the risk of stating the obvious, if the wiper behavior is not due to a mis-understanding of how to properly remove and reinstall the wipers to ensure they are positioned correctly and thus operate correctly afterwards, but instead is due to something have slipped, spun, stripped or in some physical way gotten out of sync, the disassembly is called for as this will find the problem but also find that one or more hardware items is damaged and needs to be replaced so after things are correctly installed this won't or can't happen again.

It is also obvious that the 7 hour is not a job one would agree to if there was any other way, well less expensive way, to regain proper wiper operation but if there is not, if you have exhausted all other reasonable explanations and alternatives to addressing this problem, and this is the only way, then it is the only way.

Be comforted by the fact, well the opinion of the highly informed, that the AM is a beautiful car and were I in the owner of such a car it is a car that I could look at all day even after having forked over 7 hours worth of labor and $500 in parts to have the wiper problem fixed.

 

Genuine words of wisdom. Thank you.

 

Mine's a 2006 DB9, but might be helpful?

 

Thank you! That may be very helpful.

 

Ask him to post a short video clip of the thing in operation. It would be interesting to see the movement moving.