1993 945T with leather. Driver's seat is full power with heater and memory.

The cable running from the seat motor to the inboard rail has developed, what I now understand is a common problem, of not engaging. The switches and motor all work properly. By getting under the seat and moving the cable I can get the gear to move on the track but that is just temporary.

I researched this problem on the brickboard and other sites and now understand that the repair is to remove the seat and either replace or "fix" the cable. Another "fix" was to zip lock tie the cable in a configuration where it will engage both the motor and gear.

No one showed pictures or described the exact procedure to R&R the cable when the seat is out of the car. Several posters did describe the seat as having been designed by NASA. I now know what they mean.

I was at my favorite wrecking yard today and they had a 94 940 just in. Someone had removed the drivers seat turned it over and taken the SRS module. This gave me an opportunity to see what the power seat mechanism is (switches, controller, 3 motors and 4 cables). It was a very intimidating arrangement!

Since I had been quoted a price of $300 labor and $170 parts have this repair done at an independent Volvo shop I thought I could get these cables and do the job myself.

To make a long story short I could not figure out how to remove the cables without totally disassembling the entire gearing and motor arrangement. At the motor there were two bolts on a bracket that keeps the cable in place but on the track gear I could not find any way (other than opening up the gear assembly )to free up that end of the cable. For the gear boxes that engaged the rails they seemed to be closed units.

Rather than ruin the assembly I gave up (after about an hour).

I have trouble believing that this job approaches the difficulty of heater fan replacement on a 240 but maybe it does.
Is there some easy procedure I am missing?
Are the gear units at the rails an integral part of the cable and is that why they cost $85 each?
Are there non power seats from earlier 940/60s or 740s that would be drop in replacements?

I suspect swapping out 740 seats would not work since the 940 seat is an integral part (both physical and electrical) of the SRS. I am not aware of non power drivers side 940 seats.

Your thoughts would be appreciated

Thanks
Howard 85 245 and 93 945t

OK here is the fix, one easy/ limited and one hard but corrects seat function: I researched some sites about failed front seat movement, in particular, that the console side of the driver seat stops adjusting the seat forwards or backwards, while the driver side still operates. Since one side works but the other does not, the seat begins to bind by twisting or rotating the seat and causing much stress on the working driver side motor, cable and gearbox assembly. There are three motors under the seat to control the position: One to raise and lower the seat, one to move forwards and back and one to tilt the seat. There is another motor that controls the angle of the back, but that is not part of this discussion. The motor that adjust the forward and backward position is used far greater than the other two motors. Keep this in mind as it will be important later. The mechanism that moves the seat back and forth is made up of a 12VDC motor, a spring-loaded axle, or cable and a gearbox. The gearbox uses an internal, large, rotating, nylon gear with fine teeth. This gear is part of a smaller diameter, external metal gear. This metal gear is very course and is used to move a toothed rail (part of the actual seat) back and forth. There is an independent rail, gearbox and cable for each side, but a single motor that operates both. The cable on each side is used to transfer rotation of the motor to a cylindrical worm gear which rotates the larger nylon gear and thus moves the seat rail. After much use, the cable wears out. How? The flexible cable is essentially a course, stiff spring with a round diameter. The ends are stamped into a square shape. This square cable end inserts into a square socket on the end of the motor shaft and at the end of the worm gear. What happens after much use, is that these square ends start to round off. This rounding off at the ends creates an intermittent, mechanical engagement from motor to the gearbox and thus the rail position. Once these left- and right-side rails no longer work together, then the next issues ensue: binding of the seat, leading to it becoming stuck, or rotating at best. The fix depends on what outcome is preferable. If you just want to reposition the seat so driving is possible, then play with the shape of the cable without taking the seat out. To do so, raise the seat to the highest position and tip it back to allow easy access to the front. Look for the center motor and notice the two cables on both ends. Locate the short, black thick cable on the side that is not working. Normally it is a simple 90-degree shape. Forcing the cable to have a tighter radius may get the cable to engage. Try different arrangements of the cable while operating the seat button in a direction that will straighten the seat. The goal is to positions the left- and ride-side rails so that they are once again even to each other. Once the rails are even, position the shape of the cable so that it remains engaged with the worm gear like before and adjust the seat back. Cable ties can be used if convenient to keep the engagement and increase the possibility of full seat positioning once again. If not, readjust the remaining settings, and unplug the seat (front, driver-side corner, floor), so it cannot be fooled with again. If you want to really fix the seat, the cable end needs to engage non-stop. To do so means the cable needs to be replaced or refurbished. Obviously one can locate another and replace it. Normally the passenger side cable engagement fails. Not sure why. This is my issue too. Since the cables used in other parts of the set are the same, we can just swap cables. Yes, the lengths are different, but not enough to be an issue. Swap the cable from the front motor which controls the tilt with the passenger-side cable that connects to the center motor. This cable is a bit shorter but will work just fine. And yes, the problem will now be an intermittent working tilt function of the seat. But this is rarely used once set, and it is not paired to other part of the seat that needs to operate in tandem. So, this fix should be good until you double your Volvo mileage.

Dear Alden 940,

Hope you're well! In the FAQs, there is a section on seat cable repairs. It is below, separated into paragraphs to make it easier to read.

It is to this section of the FAQs, that Steve directed the original poster.

Hope this helps and that you stay well!!

Yours faithfully,

Spook

-----------------------------

Cable Failure on One Side.

[Inquiry] My drivers power seat will not move forward or backward on one of the rails. This causes the seat to twist rather than move forward/backward.

[Response: DanR/Bob] The same motor drives both sides via cables from each end; these in turn move each side of the seat. What happened on my seat was that the inner cable's end had rounded out on one side or has pulled back inside the sheath.

The cables are round except for the last few inches where they are square. The square ends fit into the motor shaft and the gear on the track gear box. It seemed that the inner cable should have been longer than it was as just the last 1/8 inch was making it into the gear housing on the track.

Many folks have repaired this by making the outer sheathing shorter to get more of the inner cable to seat into the gear housing. Inserting a Nail to Lengthen the Inner Cable.

I didn't see any way of getting the metal sheath off the cable without destroying the ends. So I left it alone, all I did was insert 1/4 inch piece of round steel in the inside of the motor shaft to push the cable through the sheath further into the gear housing

[Tip] Cut off a finishing nail to a length of about 1/4", squareish on both ends. Drop it into the center hole where the cable fits into the motor; put the cable back in and reinstall everything.

Shortening the Cable Sheath. The cable covering can stretch and won't allow the actual inner cable to engage in the gear drive. To repair, you'll have to remove about 1/4" inch of the shrouding from the end of the cable.

[Kerry O'Connor] The end of the sheathing has a metal cap or ferrule. Cut the sheath off at the base of the ferrule. Take it off the cable, and dig out the plastic sheathing. Put it back on the cable and slide it back to the sheathing. Now the fun part: Grab the ferrule lightly with some locking pliers. Heat the ferrule with a lighter or torch, then slide it on to the plastic sheathing. When it bottoms out, give it a 1/4 turn. This will lock it on to the plastic sheathing (via the barbs). All this has the effect of lengthening the cable by shortening the outer sheath.

I've known about this power seat problem and how to repair it for years, but never had to do it until just a few months ago. Although shortening the cable sheath is the proper solution to assure full engagement of the squared drive shaft at both ends, it's a fussy procedure, especially having to do it under the seat, and using heat. The 1/4" spacer method is far, far simpler and should normally work just fine. I did depth measurements of freeplay into the drive cogs and just using a 1/4" (approximate) spacer to better center the cable in the sheath still allows quite adequate engagement at both ends. Where the FAQ says squared end of a piece of finishing nail (coat hanger wire is also fine), it just means to smooth the cut end so it's not sharp and jagged. Trickiest bit is inserting the spacer all the way into the back of the cog. It's an awkward location and you can't overly see what you're doing, so it took a few tries. Surgical clamping forceps ended up being my weapon of choice, but tweezers or mini-needle nose pliers would also work, even using a thin plastic drinking straw as a guide sleeve might work. If the spacer falls off to the side during insertion and gets stuck before getting it all the way in then you will need to extract it and try again. A magnetized screwdriver tip proved invaluable for quickly drawing the spacer back out when needed. Trickiest bit was moving a dead power seat so I could get at the seat rail bolts to raise it for proper access -tips in the FAQ worked for me.
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now

My daughter's 940 wagon had the same problem. I took it to a mechanic friend of mine and he showed me how to fix it. When the same problem popped up 3 years later I did it myself. But that was probably 2-3 years ago....
Here's what I remember:
take the seat out
turn it upside down
remove the cable from the drive motor.
This part is a little fuzzy...What happens is that the cable covering stretches and doesnt allow the actual cable to engage in the gear drive. You'll have to remove about 1/4" inch of the shrouding from the end of the cable. My mechanic used a bic lighter, I used an exacto knife. Stick the cable back in the drive and it should work. The key to all of this is that the problem is caused by not enough of the metal cable engaging the drive gears. It's really an easy fix- you can do it.
Phil C

Thank you all. I have been having the same problem, but for years the seat was in the perfect position for me so I never worried about it. Last week, it was time to pull the seat to replace some of the worn seat panels and i decided to address this (and finally clean the coolant out of the carpet from a heater core failure). I removed the cable and tested it to confirm that it was functioning. Put it back together and it tested OK. It worked once. Being an ex bike mechanic with a lot of cable housing experience, I was thinking along these lines. Thanks for the laser focus.

1997 V90

Rather than fooling with an exacto knife, heat the ferrule and push the plastic housing out the end working with the barbs, not against them. Easy peasy

Thank you for the detailed reply.

I have been to a wrecking yard and looked at the cable on a seat which was already removed.

The cable in question was in a heavy plastic covering but both the motor end and gear end were capped with a metal shroud. Was the repair simply to remove 1/4 inch of the plastic covering leaving the metal end cap or was the metal end cap also removed?

Howard

I think Kerry's got the answer.

You are correct about the heavy plastic covering.

Here's what I do:

The end of the sheathing has a metal cap. I'll call it a ferrule. Cut this off at the base of the ferrule. Take it off the cable, and dig out the plastic sheathing. Put it back on the cable and slide it back to the sheathing.

Now the fun part: Grab the ferrule lightly with some locking pliers. Heat the ferrule with a lighter or torch, then slide it on to the plastic sheathing. When it bottoms out, give it a 1/4 turn. This will lock it on to the plastic sheathing (via the barbs).

All this has the effect of lengthening the cable (by shortening the outer sheath)

Assembly is the reverse of removal.

Exactly what I did to fix ours.

Kerry

Thank you very much for your detailed reply. I will remove the seat, remove cable from motor (two bolts). Cut off ferrule, clean out ferrule plastic (which should serve to shorten the plastic sheathing), the reattach ferrule as you described.

Thank you so much for your help

Howard

I can't help you with your cable problem but I have a 91 940T with manual seats, so yes they are available.