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Volvo Maintenance FAQ for 7xx/9xx/90 Cars                                                                                                                     Version 5.0

Speedometer Failures

Speedometer Fluctuates

Speedometer Relay and ABS Lamp

740 Instrument Cluster Removal

760 Instrument Cluster Removal

940 Instrument Cluster Removal

Replacing Instrument Cluster Lamps

Replacing Switch Panel Lamps

Shift Indicator Bulb Replacement

Warning Lights Flickering: Bad Alternator Brushes

Gauges Stop Working Intermittently

Temperature Gauge Fluctuates

Service Light Reset in Pre-1990 740

Service Light Reset on Post-'89

Electric Clock Repair

Broken Odometer

Cruise Control Won't Work or Incorrectly Disengages/Re-engages

Bulb Failure Sensor Lamp Won’t Go Out

Center Console Lamp Replacement

Adding a Warning Lamp for Loss of Engine Coolant

Speedometer Failures. I do not believe it is possible to buy the gear, but it is definitely possible to have it fixed. VDO in Winchester, VA, and other places advertise. Get a copy of Hemmings motor news, you will find them in there. I believe the gears break due to people resetting the odometers while the car is moving. I have never seen this written as a warning in the owners manuals, but that is the best explanation I have seen. [Note on rebuilder:] Palo Alto (CA) Speedometer Service: (415) 323-0243. I have yet to use their services, but they were recommended by a local shop here in Boise as the best in the business. I called them last summer, contemplating sending my wife's speedo in for repair, but I haven't gotten around to it yet. The price they quoted was around $90, just to fix the odometer. [Another:] just had my electric speedo/odo repaired. know this is a common problem so thought I'd pass along the shop's name and number.

A+ emissions and speedometer repairs (Chris (904) 642-8120); 3122 #9 Leon Road ;Jacksonville, FL 32246

He's a straight shooter and keeps a clean shop. Does lots of Volvo speedo work through the mail.

[Another referral:]  I wanted to pass on contact information for a company I found here in Austin that works on Volvo (and other makes) speedometers. Its called Overseas Speedometer and you can get their contact information at www.speedometer.com . I just dropped off my speedometer to get re-calibrated for my V8 conversion and to get the odometer working again. A couple of Volvo shops around here gave him a good reference so I thought I'd pass it on.

Speedometer Fluctuates.  [Query:] My wife’s 1991 740 sedan speedometer needle simply drops to zero (as if someone pulled a socket from the wall) At this moment the odometer and trip odo also quit. Very occasionally, when driving, at highway speeds, the speedometer needle will jump back up to the correct speed, and the odometer starts working, but usually after a 1/2 mile or about 40 seconds, the needle falls back to zero and the odometer quits.  Other times everything works fine for hundreds of miles. Often when starting the car after is has been parked, odometer and speedometer never work at all.   [Response 1: Don Foster]  Check the connection at the speedo sensor. It's in the differential cover, about 3" above the filler plug. Be sure it's mechanically secure, and check the contacts (both sensor and connector) for signs of corrosion or oxidation. As much as possible, examine the harness for any signs of a break or tear, or for signs the wire might have been cut.   If it's not wiring, then it's either the sensor or the speedometer head (which is electronic).  Possibly, the power supplied to the speedo head where it's mounted in the dash cluster is intermittent.  [Response 2: Scott] Check the instrument cluster grounds under the dash and in the right footwell.   In 88 there were some 700 series cars that would register up to 60 mph while sitting still and the grounding problem was the cause.

Speedometer Relay and ABS Lamp.  [Query:] I recently brought my 1987 Volvo 760 GLE with 200,000 miles in for repair after I noticed that the speedometer, odometer and cruise control stopped functioning.   The car does have ABS and the ABS dashboard light also went on full-time just about the same time as the speedo/odometer/cc went out.   [Response: Zippy] The speedometer converter is a relay looking device that is under the left side modesty panel (under dash piece) that has its own fuse mounted to the top of it.  You hadn't recently jump started your car's battery have you? Done incorrectly it is very common for this hidden fuse to blow, rendering ABS and the speedometer inoperative. This only happens on the older ABS cars.  See also ABS Lamp Lights After Start-up

740 Instrument Cluster Removal. It's very simple. take a super slim screwdriver and remove the small plastic cap surrounding the small clock set knob on the left and the cap surrounding the dash light dimmer on the right. Under each of these is a phillips screw. Remove and pull the whole cluster out. Don't even need to remove the steering wheel. If it 's the first time out, the wiring will be held in tight behind the dash by plastic ties. You can cut these ties which will afford you enough room to twist the cluster around and replace any bulbs etc, or mark each electrical plug and unplug enough of them to give you the room you need.

760 Instrument Cluster Removal. [Query:] I can not figure out how to get the instrument cluster out of my 89 760. It looks like all of the trim around the dash switches has to come off, then take a couple of screws out on top of the dash insert. I can't seem to make anything move.  [Response:  Chris Ascoli] I found out the hard way. Besides the two screws in the upper black insert, there are I believe 3-4 more screws hiding behind the air vents, one per vent.  Take each air vent and push the top all the way into the dash as if you want to shoot the air up at the ceiling of the car. Once you do this, you should be able to see the screw in the upper portion of the plastic JUST behind the top of the vent.   It's kind of tricky to get at, but you should be able to squeeze a Phillips head in there and remove them. Forget to do this and you'll hear a Crrrrrraaaack of the plastic housing surrounding the temp controls, etc. As you can imagine, that's how I found the screws.  Chilton's did a fantastic job of NOT telling me about them. Thank God I didn't break it enough so that it hung away from the dash when reinstalled.
    Once you get the vent screws, just pry with a little force and it should come out. But if it seems to hold up somewhere, check for any other screws at the binding point. The vent ones are definitely key though.

940 Instrument Cluster Removal.  [Query:]  How do I remove the instrument cluster in my 940?  [Responses: Abe Crombie and  IanB] We got it out with a small screwdriver which will go through the slots in the side of the plastic bezel.  You will feel a spring clip as you push into slot. Push the clip hard while pulling toward you with the shank of driver; the clips are attached to the dash and are also robust, not easy to damage.  The surround is alloy and is held by the cluster screws.   There are lugs cast into the sides of the surround onto which the clips lock.  Do one side only, it should come out easily once you get one to let go.  One clip each side, nothing else holds it in.  After you get it out remove the cluster by taking out (4) Torx screws and it's out.   If it's turbo you have a gauge hose to disconnect at a joint about 8 or 10 inches from gauge. The latter is easier to do with the kickpanel above brake removed.  To replace the bezel simply push it in and the clips lock onto the lugs.

Replacing Instrument Cluster Lamps. [Query:] I have a 740 gtl 87.  How I can replace bulbs behind the clocks (speedometer etc.)  [Response: Peter James ] At the base of the instrument panel under the clock adjustment and trip reset buttons, towards the ends there are 2 rectangular panels about 5mm high by 35 mm long. Lever these out with your fingernail. Underneath there is a phillips head screw. Undo both and the whole instrument assembly will pull straight out, limited by the wiring harness plugs and the hose for the boost gauge. I usually disconnect the hose which gives you enough space to get your hands/fingers in to turn the lamp holders and remove/replace the globes. You can disconnect the wiring plugs but I don't bother, I put a mirror up on the top of the dash against the windscreen with bluetack and work from the drivers seat.  Hope this helps.

Replacing Switch Panel Lamps.  You're actually referring to the switch panels (or whatever it's called).  I don't know offhand if the '89 740 has the same style of instrument cluster as the earlier ones -- I know the 760's changed in '88, but the 740s didn't until later -- 1990? Anyway, probably the easiest way to get to a burned out bulb there would be to remove the instrument cluster. If your instrument cluster has a clock adjustment knob on the bottom left corner and a dimmer adjustment on the bottom right corner, the two plastic strips they poke through can be pried off, revealing two phillips screws. These screws are the only things holding the instrument cluster in place. Remove them, slide out the cluster, and you should be able to place it on the dash. Then you can reach down in the opening and fish around for the burned out bulb. A dentist's mirror or equivalent may help you in your search. If your '89 has the later style instrument cluster, it comes out in a similar fashion, but there are clips that hold it in place located on the sides of the cluster. I've never pulled one of these out, so I don't know how much more difficult or easy it is compared to the earlier style.

Shift Indicator Bulb Replacement. Shift Indicator Lamp.  [Query:] How does one replace the bulb that illuminates the gear selector letters?  [Response:] Here’s how it can be replaced:
                     1.remove ashtray
                     2.remove plastic cover under hand brake
                     3.remove two screws that 2. revealed
                     4.remove plastic cover that covers shift gate
                     5.Look under shift gate on left side for two wires connected to light
                     6.pull down gently on wires and the light appears
                     7.replace bulb and reinstall in reverse order

Warning Lights Flickering: Bad Alternator Brushes.  [Query:] We just replaced our battery because as we drove the warning lights were constantly flickering on and off (plus sometimes we had to jumpstart the car to start it). Now the car starts fine but the warning lights continue to flicker. Any idea on what could be the problem? [Response: Russell Smith]  Check the brushes in the voltage regulator. Most likely they are worn out, causing the idiot lights to flicker and preventing the battery from charging adequately.

Gauges Stop Working Intermittently. Has anyone experienced a situation where all the gauges in the binnacle act as if they are not getting any power? 2. Has anyone experience a situation similar to 1. above, but where the gauges seem to take turns taking a swan dive? [Response:] Have seen this problem on a 85 / 740 turbo. I took out the instrument cluster and tightened every screw and connector I could get at and this fixed the problem. Talking to a Volvo mechanic, he said there is also likely that a ground is bad on the computer module situated near the passenger side, side wall.  [Response 2:] For what it's worth, my '90 745 had the gauge problem intermittently.  Drove me crazy, and the dealer "tightened the grounds" four times, each with a positive effect for a short while. They did give up, saying it was mostly likely a cracked p.c. board in the dash, which would fail as it flexed. Wouldn't know without pulling the dash. I sold it. Problem solved.

Temperature Gauge Fluctuates.  [Query:] I just noticed my heat gauge flutters from the left to middle (not into the hot Zone) . There does not seem to be any pattern to this, smooth roads or bumpy, acceleration or slowing , whatever. It looks normal for a while, and then starts getting the jitters.  [Response: Steve Ringlee] To test your gauge, get an appropriate resistor from an electronics store (preferably with a 5W or above rating +/-5% tolerance), solder an alligator clip to one end and a quick disconnect connector to the other. Pull your gauge temperature sensor connector from the sensor (the one under number two cylinder intake manifold on B230F engines) and insert the quick disconnect into the half of the connector wired to the gauge (not ground). I recall that out of the panel this wire is yellow-white. Check your wiring diagram to confirm this. Attach the alligator clip to ground and turn on the ignition. Your gauge should read in the hot end if it works. If it doesn't, then either the gauge or the wiring harness to the gauge is faulty. Clean wiring connectors with electronics connection cleaner (such as DeOxIt) and test again. If it reads correctly, then the sensor is bad.

Resistor ratings for 7XX/94X cars are:

 Cars from 82-86: 87 ohms to get a 90C reading at the gauge
 Cars from 87-93: 206 ohms to get a 90C reading at the gauge
 Cars from 94 on: 75 ohms to get a 90C reading at the gauge

Electric Clock Repair. The Clock Works; (Automotive Clock Repair & Quartz Conversions - Most Service Completed Within 24 hours) at 1745 Meta Lake Rd., Eagle River, WI 54521-8531Contact: Jerry Magayne Voice or Fax: (715) 479-5759 E-mail: clockworks@juno.com

Broken Odometer. I have found a solution: at the pick and pull I can get an instrument cluster for very cheap (10-25% of the repair estimates). I just unscrew 8 screws at the back of the board and remove the cowl and lens. Then take 4 screws out of the white speedo housing to pull it free. This can be transplanted easily into your recipient cluster and even a slightly different 1990 model works well in the 86 cluster after removing the service reminder reset cable that the later ones come with. Who needs that function anyway? To reset the mileage to your correct (but by now estimated) figure is also trivial once you remove the small white electric motor that drives the odometer, and slide the pin holding the small exposed gears. The odometer digits now rotate freely. No cheating at this point. (The members of this list are probably the only group of owners who would not be tempted to roll back mileage, but instead might be tempted to add high status mileage to their cars!). Most of the speed-odometers are the r9800 variant but compatibility is something to check for in the replacement. Apparently, this number keys it to the rear end properly. This is also a swell time to throw in a large tach if you can get one.

Service Light Reset in Pre-1990 740.  [Procedure:] There is a reset button on the back side of the instrument cluster. It is located about where the 70 mph reading is, on the back side. You may be able to get your hand up from the bottom to press the reset by first removing the lower kneepad. You can also remove the two outer lower screws on the instrument cluster and gently pull out the instrument panel enough to get your hand behind to press the reset button. There is just enough slack in the harness to allow pulling the assembly over the steering column to get at the reset button. Remove each small plastic cover to expose the mounting screws. The speed nuts that these two screws go into like to fall off, down into the dash area. A lot of people just remove the service bulb on this model to avoid the trouble of having to reset light every 5000 miles.

Service Light Reset on Post-'89. On the post-’89 700/900's there is a small black, circular rubber plug in the clear plastic of the instrument cluster. Carefully remove the plug ... then take a very small phillips screw driver or even a nail and push in the re-set pin just behind the hole in the clear plastic. Replace the plug and the service light is re-set.

Cruise Control Won't Work or Incorrectly Disengages/Re-engages.  [Response 1:] Most common problem that I have seen is either split or disconnected vacuum hose, or mis-adjusted brake switch (at the pedal) or clutch switch (if manual tranny). Sometimes it is simply that the brake or clutch pedal is not fully returning - try lifting up on the pedal with your foot while driving and see if you can engage the cruise. In addition to the vacuum switch, check for operation of the brake light switch. I seem to remember that the vacuum switch will disengage the cruise simply by releasing the vacuum from the unit, but the brake light switch must activate in order to release the control unit signal. If you are just tapping the brake lightly to disengage the cruise (as I often do), but not activating the brake light switch, then it may simply re-engage as soon as vacuum is applied again.
[Response 2:] Pull hose loose at "T" fitting aft of throttle servo.  Apply vacuum (suck on it, but make sure no one's watching) to fitting with hoses that run down to pump and into car to brake pedal defeat switch.  If leaks are detected here then find split hose or go inside and find pedal switch fault. If no leaks detected then closely inspect the servo for splits or tears.  The likelihood of electrical trouble is far lower than having a hose split or a leaking servo.

[Query:] The cruise control on my sister's 1993-944 will engage only about 10% of the time it is activated. Per past posts I checked all the vacuum lines and the servo with a Mityvac tester and they hold a vacuum, indicating no leaks. I also checked the functions of the cruise switch on the turn signal lever, by disconnecting the harness connector, with an ohm meter and it checks out. The fuse is also ok. I tried to use the "B" diagnostic socket with the wire put in  the #2 hole. I turned on the ignition and pressed the button and nothing happened, no codes flashed, not even a 1-1-1.
[Response 3:] There is a separate switch with a vacuum line attached for the cruise. If the car is manual tranny, the car would have two switches, one for each pedal. If the switch adjustment is marginal, i.e., there is not a definite “off”, then the switch needs to be adjusted. It is adjusted the same way as the brake switch.
[Response 4:] Mine did the same thing and the problem was the bulb failure relay/device in the relay compartment. When this fails there is no ground for the cruise and the brake lights won't work.

Bulb Failure Sensor Lamp Won’t Go Out.  [Query:] My left low beam failed, and my bulb failure warning light dutifully advised me of the need to replace the bulb. I replaced the left low beam, and all the lights on the car work now. But, my warning light is still on, though it goes out when I flip to high beams. Anyone know a fix for this?  [Response:] The bulb failure sensor works on current flow. If the bulbs are miss matched, say a Wagner bulb on the left and a Sylvania on the right, chances are they have different resistances.  This causes different current flows to each bulb and the light on the dash will come on.  You may just want to change the other headlight and hope that stops it, or live with it.  Also, corrosion in the connectors in the circuit that the head lights are on can cause the indicator light to come on.  It can be very frustrating, and I know many people that have pulled the little bulb out of the dash.

Center Console Lamp Replacement.  [Query:] Does anyone know how to replace the light that illuminates the inside of the center console and the rear ashtray? I can't figure out how to get in there.  [Response: John R]  The plastic panel on the rear of the centre console clips out, but it is very hard to pull out, feels like it will break. Try removing ashtray and then gently pulling around bottom of the panel. Once this panel is removed you can gain access to lights (also gives you access to the handbrake adjustment).

Adding a Warning Lamp for Loss of Engine Coolant.  See Loss of Coolant Sensor for Volvo 740/940 Cars for more information as to how to add this sensor and warning lamp.

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