I would guess you have already looked through the FAQ's and found the section on failed speedometers:

https://www.brickboard.com/FAQ/700-900/ElectricalInstruments.htm#Speedometer_Failures

There is a hot link there to Overseas Speedometers (https://www.speedometer.com/)

Several years ago I posted in this forum about my contact with Overseas Speedometers with an inquiry about repairing a failed speedometer in a 1991 740 with leaking/failed capacitors. The nice/timely reply from them said that yes they had repaired them in the past but no longer did. Apparently they had had an employee that accepted the challenge of removing the old capacitors and cleaning up the board that had been damaged due to the leakage and sometimes had good results. Because of the amount of time involved and mixed results at the repair attempt they no longer accepted those speedometers for repair. I looked for my post but was unable to find it even with a Google advanced search. you might contact them to see if they can provide any leads for a repair.

The other approach is to source a 1993-94 940 cluster and swap it into your 1991. The speedometer will work fine without any alterations. However the gas gauge won't register.

The work around on the gas gauge is either swap out the sending unit in the gas tank or alter the circuitry in the cluster. I worked with another brickboarder on the necessary steps and then wrote it up. I think it might be in the FAQ's as sort of an addendum. I also must have it on my harddrive somewhere but off hand I'm not sure. If the cluster work around is of interest to you let me know and I will organize a search.

EDIT:
The search was successful. Here are two links that might be helpful:

https://www.brickboard.com/FAQ/700-900/ElectricalInstrumentClusterInterchangeability.htm

https://www.brickboard.com/FAQ/700-900/ElectricalInstrumentClusterInterchangeability.htm#FuelGaugeClock

Randy
--
Any twenty minute job is just a broken bolt away from a three day ordeal

Hi,

I’m surprised that no one has responded to your post.
I’m a totally 240 person but there some people still rolling around in the 700 series but you have to know the 700 and 900 series have different speedometers made in Japan, i think from the name I have seen on the back of them.
Since it’s a 1991 that puts in the age of when the 240s were still being produced.
I see that you are saying you are from Oregon state so at least you are on the west coast.
I have dealt with the Wagonmeister down in the mid state of California, Near Bakersfield or Lancaster Ca.
He is into refurbishing Volvos and has a collection of speedometers for the 240 series clean and repaired himself I think?
On his web site he lists a service for them but he might have other models of things as he occasionally details out other car for other clients.
He details every inch of his project’s vehicle. At least every inch that can be reach or seen and the cars are absolutely road worthy. He has made a reputation doing it for $$ but if you want it done right expect that.

His web site is chocked fairly well with products he sells.
He is very knowledgeable since he does refurbishments so that goes in hand knowing people and most repairs of course.
I would contact him at his web site Wagonmeister.com. Email or by phone he responds to both.

Another persons web site is Dave Barton.com. The flying moose as I recall.
I was told that Sweden has mountains and moose. It is one reason the Volvos 240 were tough and large enough to get in and out of. That is, when compared to the Japanese cars of that era.
The Swedes are husky people in size and strength so it suited Americans to consider downsizing from their land yachts of the previous decades.
About 2 million cars were sold of the earlier series of 50 years or so of building them.
They stayed European until the break out of Peugeot and the demise of Saab/GM. A little TOO different of style and configurations for the American market, IMHO.
Helps explain how there an early model Volvo following today.

BOTH are worth a shout out! 😀. It’s your cab.

Phil