Hi,

It might be of interest to you to read the following post

https://www.brickboard.com/RWD/volvo/1606775/220/240/260/280/91_240_4_3_pin_speedometer_swap.html

It's titled 'Speedo Swap' but it describes a problem I had that was very similar to your own. It's seen over 3 years of heavy use since then and the fault has not returned.

It's impossible to say for sure, but my suspicion is that the cure is related to the re-tensioning of the receivers of the speedometer pins. There are 3 of these on the back of my 91 non-ABS, where you will find 4.

With the cluster out, you might want to look for other signs of a bad connection at the L connector or the ribbon fuse on the back of the speedo.

I hope this helps.

Peter

Hi John,

So you’re having some charging problems eh!

I don’t know the exact D+ voltage but that does seem very low but then I don’t know how you are measuring it. Disconnected or connected to the alternator or with the engine on or off and the key in position two.
In either case the instrument panel is yelling “ I got a problem around in here.”
So many lights! It must be a power in issue or a ground needed for all of them to go back!

The exciter current comes from the instrument cluster and goes out through the gray firewall connector.
From there the wire runs down under the engine.
On the alternator there are three wires. The big red one is the Battery, the exciter wire and a grounding wire for the housing. This is because the alternator is rubber mounted.
A many of times they are found broken or frayed.


For the sole purpose of troubleshooting it is best to start from any power supply source and work outwards.
So going back to the beginning, the power to the instrument cluster is provided from the drivers door fuse panel. This is a convenient place to have one but bad for condensation of water to end up.
Wet shoes on the floor mats provide a nice condition for this.
Cleaning all the fuse clips and the fuses themselves is a good maintenance idea. Using a spray corrosion inhibitor is advisable every couple years.

I found this post, from Art Benstein, showing the exciter wires path and the years covered. It’s Mostly from 1986 on.
https://www.brickboard.com/RWD/volvo/1593194/220/240/260/280/93_245_batterycharging_issuediagnosis.html

You mentioned the instrument lights several times. It was a little confusing when there was no lighting and how many? If it’s all the way across, my thought is it could be a corroded fuse and causing the intermittent frustration.

It looked like he referenced fuse 13 as being the input fuse in “most” cases. Cleaning them all is best thing to do.
It’s not nice when the windshield wipers go “intermittently off-on” during a stormy drive!

The overdrive light may be a separate circuit and entirely driven from the automatic transmission switch. This would explain the reason it lights correctly. My 1993 manual does not have one as I removed that ECU shift up nuisance.



Looking at the path drawn in Art’s layout you could jump out to firewall connector or if.... nothing has voltage.... go back?

If you had the instrument cluster out for the temperature compensation board removal or a speedometer gear, you made need to check the “flex fuse” located over the top of the speedometer. Some people get overly enthusiastic when pulling perimeter screws when splitting open the back of the cluster.
Make sure the two screws are holding the trace film firmly down under the screws to their contact points.

From there out it’s the firewall connector that may need some TLC.
As it turns out, the Same goes for all wire terminal ends and in any place there are! Corrosion knows no boundaries.

Hope this helps in some way!

Phil