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Wacky Temp Guage: Compensator or Voltage Stabilizer?[240-260/1989] posted by bud man-volvo fan on
Tuesday, 14 July 1998, at 11:09 a.m.
There has been much written here about the temp guage and the "temperature compensator board". I have an '89 that exhibits this guage problem, actually since it was new. I have Volvo-published wiring diagrams for this year and model. Now I'll admit that I didn't survive EE at Georgia Tech, but I know enough about reading a DC schematic to see that there is no such thing as a "compensator board" on THIS car, but there is a "voltage stabilizer" or regulator plugged into the back of the IC. Could this be my problem? I see no other component between the temp sender and the guage.
I called RPR yesterday to order a stabilizer. They instead steered me to the compensator. I questioned whether it was really on the '89 model, and they replied "yes", the car has both, and referred me to Bentley (which I don't have). I declined to place an order.
Can someone please cut thru the fog and give me the poop on the '89? If I'm going to purchase a part, I want the right one, since electricals are non-returnable.
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Re: Wacky Temp Guage: Compensator or Voltage Stabilizer?[240-260/1989] posted by ted on
Tuesday, 14 July 1998, at 12:40 p.m.
bud-man,
yes your 89 240 has a temp comp board volvo p/n 1363117. it also has a voltage stablizer as well. the temp comp board is inside your instrument cluster.
the p/n for the stablizer is 1362674. i strongly recommend replacing both pieces.
there sometimes is a corrosion build up on the pins where the temp comp board locks onto. cleaning somtimes helps. there is also a way to solder the connections permanetly, although i don't recommend it. take care to install the
board, you can break the pins! in our shop we normally replace the board and the stablizer together, because it is less headaches, especially for come backs.
ted
stillman volvo
Re: Wacky Temp Guage: Compensator or Voltage Stabilizer?[240-260/1989] posted by Don Foster on
Tuesday, 14 July 1998, at 12:48 p.m.
I know for an absolute fact that the '86 240 has a so-called "compensating board" because I've removed and resoldered it (thus solving erratic temperature readings). Your '89 is probably no different. It doesn't take long to remove it -- here's how:
- To the left of the cluster, remove the headlight switch knob, instrument light knob, plastic panel, and the metal bracket. You may also have a switch in the panel -- let the panel dangle.
- To the right of the cluster, remove the clock bezel and lower blank panel (or, if a DL, the two blank panels).
- Remove the screws on the left and right side of the cluster.
- Carefully pull the cluster straight out until it clears the dash. A little prying, wiggling, or jiggling may help, but don't force anything.
- Unplug the wires and harnesses from the back of the cluster PCB. Make a sketch of what goes where -- not only will that help you on reassembly, but it'll prevent you from forgetting to plug something back in.
- Remove the cluster by sliding it to the right behind the steering wheel.
- Put the cluster face down on the bench (use a towel to prevent scratching the plastic) and remove the 7 (I think) screws around the outside of the PCB.
- Lift the PCB away from the cluster. The compensating board is about 1" by 3" and is plugged into the backside (inside the cluster) of the main PCB using edge-connector pins (long edge).
- These pin connectors may be giving poor contact and causing the problem; you can clean them with something abrasive to remove oxide (I use a pencil eraser). Remember to clean out any residue.
- At this point, you can install a new compensating board or try resoldering the original one.
- To reassemble, carefully follow the steps backwards!
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Tuesday, 14 July 1998, at 5:35 p.m.
budster-
the following is a direct tryping from Bentley page 380-5
"On 1985 and later models, a temperature compenstaing circuit board was installed on the back of the instrument cluster to stabilize the temp. gauge reading at high engine temps.
If the temp. gauge operation is erratic or the gauge readings are always on the high side, there may be a poor electrical contact between the instrument cluster printed circuit board and the temp. compensating board. This is caused by excess solder flux on the board.
BEFORE REPLACING THE BOARD , BE SURE TO TRY CLEANING THE CONTACTS FIRST!
*NOTE* Four different temp. compensating boards are used on the Volvo 240 models depending on model and chassis number. When ordering a temp. compensating board, be sure to have the vehicle chassis number on hand.*
To replace the Tempp. Compensating board
1) Disconnect the neg side of the battery and remove the instrument cluster .
2) Carefully remove the printed circuit board from the rear of the instrument cluster. Then pull the compensating board from the instrument cluster housing.
3)If reinstallinbg the old board, carefully clean the four (4) contacts on the board using a thin sharp object. Use care not to damage, distort or bend the small contacts.
4)Clean the contacts on the rear of the instrument cluster using a sharp knife.
5) Reinstall the temp. compensating board and the printed circuit board."
Also a simple check device can be made using a 68 ohm resistor (make up the appropriate number at Radio Shack) and install it in line with the wire (yellow) coming from the temp. sensor in the head below/near the distributor. Turn the key on and the gauge should read 3/4 tank. (Do thois after the temp board fix to check the accuracy of the repair).
Credit Robert Bentley Publishers 240 Guide....please don't sue me I'm only trying to help.....
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"OK Butch, you take the one on the right and I'll take the 6 on the left" The Sundance Kid to Butch Cassidy when first meeting an IRS Audit team...