Interior: Seats, Etc.                                                                                          FAQ Home

Seat Heater Functional Diagnosis.  [Response: ] I had the same problem and decided to remove the cover (by removing the side clips from the seat) to the bottom section of the seat (the part you sit on). While inspecting the warmer unit, I noticed that one of the connectors attached to the thermostat (mounted in the middle of the heater unit) had come loose. I have since heard from others that this is a fairly common problem among Volvo seat heaters. After reattaching the connector (and making the connection more permanent) the seat toasted my bum like a charm.  [Response 2:] How to troubleshoot the seat heaters:
1. Are fuses good?
2. Check seat heater switches to ensure they are good. Contacts may require cleaning, since they are in an area that accumulates dirt and debris.
3. If your car has leather seats, it will have a relay. Cars with cloth seats (probably only GL and base models) lack a relay and have the thermostat direct in line with the heater elements.  The relay may have come loose, or it may suffer from internal solder breaks.  Remove, re-solder, and reinstall.
4. Remove seat cover and trace continuity on seat heater harness. Sometimes the connectors to the thermostat break, sometimes the wires to the element break right at the edge of the element.  There are often breaks in the harness that develop over the years. It seems to be much more common to have a problem with the wiring than with the thermostat. I've found the connection often becomes loose right at the thermostat--I actually resorted to soldering one thermostat in place--no more problems!  Repair breaks with soldering. Simple way to test the thermostat is to check continuity after placing the 'stat in the refrigerator for awhile.
5. If Steps 3 or 4 show the seat heater to be ready for retirement, replace with a new seat heater. Cost will be around $100.
Repeat process whenever seat heater malfunctions, or every five years, whichever comes first. (Seat heaters commonly start to fail around the five-year mark).

Seat Heater Removal Tips. Just fixed my driver's side seat heater on 740GL; the resistor wire was broken. The biggest problem during the job was removing the seat. Took me a while to find the right position in which the seat would come up. I left the original heaters on the place and only put the new ones under the seat cushion. Another problem point was getting the springs under the seat back to place, the spring force is quite large. You can test your heaters with an ohmmeter, readings should be around 1-2 ohms. If you get 3-4 ohms they're still probably ok. I got seat heater elements from local dealer for $17 which is much less than original Volvo stuff.

Seat Heater Switches. Examined the switches for the electric seat heaters. Both sides had stopped working within the past year, and I had assumed the seat wires had failed. Surprise! Neither switch functioned; the contacts were dirty. It's a bugger to get the switch apart, but it's a simple hi-amp contact that's easy to clean. This is probably a common failure mode.

Seat Heater Switch Removal.  [Query:] Any advice on how to remove the seat-warmer switches?  The little orange "heater-on" indicator light is burned out, and I need to get at the switch for the purpose of replacing the indicator bulb.  {Response: JohnB] On my 90 they're just clipped into the center console.  I remove the screws under the parking brake handle and up comes the center panel and a bunch of wire harnesses.  Carefully pop the harness connector off the switch and pop the switch out for replacement or repair.

Seat Heater Relays. I had the same thing too. The problem (in my case, anyway) is the relays. They are under each seat, and can be unclipped and removed. The usual relay-death-syndrome, i.e. broken solder joints, is the culprit. Just re-flow the solder and your bum will heat up once again...

Seat Heater Failure Diagnosis: Terminals. Seldom is a non operational seat heater due to a broken element. 90% of the time it is a break at the spade connectors at the stress point near the thermostat or the thermo itself fails or no voltage to the connector under the seat, test for continuity with a meter through the under seat connector when ambient is below 50 deg F with seat heater switch off or under seat connector unplugged. Seat heater thermo is accessible with seat installed. if u move the seat fully forward and incline the back to its most upright position u can look how the upholstery is attached for the bottom cover. Its simply a spring loaded bar. pull it out of the two side attaching holes. recline the seat fully back and then pull the detached end thru the fold between the seat back and bottom then gently pull it over the bottom to reveal the seat heater webbing. slide the webbing out gently and u will see the thermo is pretty obvious how to replace the thermo. If disconnect the thermo use the ohmeter to check the continuity through the back cushion. you must use a heavy wire cutter on the wire clips that hold the upholstery in order to access the back heater. other wise removal is similar. I used plastic wire ties to replace the cut wire clips to refasten back upholstery. Has held for many years. Installation is the reverse of above. the only difficult part of the operation is getting that spring loaded bar back into the attaching holes under the seat.

Seat Heaters Over-Heat.  [Query:] I have a problem with my driver’s side heated seat. Last winter it basically cooked my ass. It got so hot that I had to pull over and get out the car and then get it shut off with the switch. If I turn it on it comes up to temperature immediately almost and it gets super hot. Its almost like the element is right at the leather on the bottom seat. Now the thing doesn't work at all and I'm not sure how to proceed. The switch lights up and appears to be allright. I guess its either a bad thermostat or element.  I'm not sure where any of these parts are located.  [Response 1:] had the same thing too. The problem (in my case, anyway) is the relays.   They are under each seat, and can be unclipped and removed. The usual  relay-death-syndrome, i.e. broken solder joints, is the culprit. Just re-flow the solder  and your bum will heat up once again.  [Response 2:] It could be that the relay or the thermostat that controls them has a problem.

[Further Query:] I got a new switch.   Its easy to get the switch out, the tricky part is the harness, and the front seat cushion, Anyone know how to remove the cushion? the harness disappears under the carpet, any ideas where and how much of the carpet to lift up?  Why Volvo decided to have a 24 inch harness on this switch has got me, you would think a connector could have been built into the switch housing, and tie right into the main harness.  [Response: Bob] You can pull up the front part of the cushion. The front part of the seat cover is attached by a rail going side to side. Usually has a clip in the center. Remove the center clip, grab the center part of the seat cover where it wraps around the seat frame, bend the rail out in the center so it will come out of its holes on each end. Then you will find an S hook attaching the cushion to the frame about 6 inches from the front. 1 hook on each side. The wiring plugs in near the outer seat mounting bolt. There is a plastic cover attached with 1 screw at the front of the left adjustment rail. Remove screw and cover, pull up the carpet slightly and you find the 3 connectors for the switch. One connector may not match, as they changed them. If so, you can either order the plug and terminals at the dealer or splice color for color.

an electric drill,

drill bits from 11mm downward,

hacksaw or grinder and file,

and a small nail or pin.

Seat Removal. To remove the front seats in the 700/900 series, remove the seat belt retractor from the seat, If it's a power seat, disconnect the wire harness connectors located near the left front corner of the seat track (driver's seat.) Then remove the four bolts that secure the seat tracks to the floor. There are two lugs mounted to the bottom of the seat tracks- one per side that fit into "keyhole" slots in the floor structure, so once you get the four bolts out slide the seat aft to disengage the lugs and lift. It's much easier on your back if you have a helper to maneuver the seat out with out tearing up your door panels etc. Why the lugs you ask? My only guess is because the seat belt retractors are mounted to the seat instead of the "B" pillar and the engineers wanted to make certain the seats stay put in a crash. (my opinion)

Seat Back Removal for Heaters, Lumbar etc. Have the seat out. It might make the job easier to separate the seat back and the bottom, although it's not strictly necessary. To do so, remove the 4 bolts that point their heads inside, under the rear of the seat bottom. To open both the seat back and the bottom, you will have to bend/cut the small wire clips that hold together the rods at the end of the upholstery. You can try to reuse these clips at reassembly, but I usually just use those plastic ties used found at automotive stores in a multitude of colors. For the bottom, the upholstery is also held on the side of the seat by small hooks protruding from the frame. These should be easy to deal with. There is also a bigger metal clip on both sides that has to be forced off. After removing all these, you should be able to peel the upholstery back after unhooking the metal rod at the back end. There is also a metal rod held down with some clips at the center of the seat. For the seat back, you have to remove the small plastic panels on the sides of the seat (right side this means removing the knob for rake adjustment first by turning the locking ring inside it). You should also remove the lumbar support knob: just turn it CCW till it comes out, then the base should just come off. As for the above mentioned plastic panels, the bottoms snaps out, and then you push upward to unhook it (it's pretty tricky and I have broke some, I hope I remember correctly the setup!). Once you removed these plastic panels, you'll discover similar small hooks as on the seat bottom. After unhooking those, you should be able to pull up on the seat cover and get the job done. This is a great opportunity to repair a broken lumbar support mechanism!
[Response on lumbar adjusters: Zippy]   What breaks on the 700 series of cars is the screw adjuster that the knob handle turns and thereby tightens the strap that is the support. To repair it you open up the seat back and replace the lumbar "adjuster".

Headrest Removal. [Note 1:]It's a game of blind-man-buff... there is actually a hook/latch holding the two rods.. you have to press down at the back of the seat about 6 inches below the top of the back to release them. [Note 2:] There are little tabs that you have to push on each of the legs of the headrest, inside the seat. Some people claim they can do this through the seatcover, from outside, but I couldn't. I had to open up the seat and reach up. If I remember correctly, you have to push sideways. I guess it's worth trying before you open up the seat.

Vinyl Repair. I found that a clear PVC solvent adhesive does a real functional job on repairing tears in vinyl upholstery. It's sold in tubes at Walmart for $3. Called "Tear Repair". Call 800 248-Poxy

Leather Seat Repair.  [Query:] The carpool  has taken its toll on the mothership (wife drives the car).  What is a good option to get the front seats recovered, as the local guy says that he only has vinyl (yuk). or do i have to buy the whole seat from the junkman?  New leather covers are available from the dealer at about 1300 bucks for each seat.   [Response:] I had a '90 760 wagon with ruined seats as well.  Instead of doing the dealer rape, I took it to a local auto upholstery shop.  They took a good look at what needed to be done, and suggested they replace the panels in the seats that were either worn, cracked or torn.  They replaced the panels, and then redyed the whole seat to its original color.  This was done to both front seats, and the dye was put on the whole interior. They also put in a brand new headliner for me, and fixed a few nick nicks around the interior.  The whole job cost me $500.  I think that might work for you instead of bending over at the dealer.  [Response 2:]   The driver's seat on my '92 940 has some cracking in the leather so I took it to a local upholstery shop that is well respected around here. As we discussed the options for proper repair, he told me he gets all his replacement leather from a supplier who dyes the leather to match what's already in the car--He clips a small sample from under the seat to use for color match. This upholstery shop then sews up the replacements.

[Tip from Gennaro Lopez] I've taken off many a 240 seat and repaired the upholstery (shoe repair shop does wonders with the leather). Now I'm gonna tackle the wife's 740 sedan. Passenger's seat has a rip in the middle of the seat. If I can remove the leather skin, I'll take it to Guiseppo at the shoe repair place and he'll sew a thin piece of leather to it for about $5.

Seat Cushion and Skin Removal.  [Query:] Are the methods for removing the seat & seat skins similar between the 740 and the 240? Any hints to avoid trouble?  [Response: Bob] There is a bar going through the upholstery front and rear, similar to 240. You should remove the seat pocket- 1 screw on rear, spring loaded retainer on front. Looking from under pocket, you will see a hole with a spring and round plastic thing. Stick a screwdriver in and press the retainer toward the seat, and gently jiggle the pocket upward. Then you will find a steel hook about 4-6 inches from the front of the seat cushion. Push the hook toward the center of the seat and unhook from seat frame. Pretty straight forward. I usually leave seat bolted down. However, if you decide to remove it, after unbolting all 4 corners. you have to slide seat back a bit and then lift. There are slots in the floor with holes (key shaped). Not too difficult.

Color Issues.  If you have color problems due to scratches, etc., try a local art supply store and look for those solvent-based permanent art markers that come in a myriad of colors. There is usually a good match in color to be found (although watch color density: the lighter densities work better). Use the marker to color in the  scratches, etc. and reduce the color contrast.   If you need to re-dye areas of the seats, the dye used in detail shops is from Fitzgerald's and they can be reached at 800 582 3326. The seats do look good.  Of course I'm still going to get some Lexol and treat them to keep them looking good.  [Tip]  Here's a commercial site with a great deal of useful information about leather repair: http://www.leathermagic.com/

[Tip from John Acampora]  All of the guys on my Mercedes list swear by Leatherique http://www.leatherique.com. They have stuff to repair cracked dashes and re-dye/maintain leather.