Thanks to everyone, especially the wiring diagrams!

I pulled the cluster tonight for the nth time. Gosh I hate pulling that thing.

I tested the wire and it was fine. I took the cluster inside and did a continuity of the pin to the top of the temperature gauge. Sometimes it would buzz and sometimes it would not. I noticed that when I pushed down on the top of the connection that it would work better.

Anyways I tore the whole cluster apart and found nothing. No cold solder joints or broken traces.

I put it all back together and I was still getting intermittent checks on the pin and the top of the gauge, and I had even tighten nuts really tight. So then I got to thinking, I know its dangerous. I need a little more surface area on top of the small washer and how the nut connects to it. I found two larger washers and put them on top of the smaller washers and then put the nuts back on.

I no longer need to apply pressure now to get a reading so I think this will work.

I put it all back together and while I was buttoning everything up I started the car. Within a few minutes the needle started to rise and show that the car was getting warm.

I'll know more on Saturday when I take the car out while hunting. I'll report back then.

Regards,

Matt

Keep in mind that the temperature and fuel gauges depend on a dependable voltage source, namely the solid-state voltage regulator attached to the back of the instrument circuit board.

Both gauges actually are indicating small but varying amounts of current flowing through them, regardless of their individual scales (fuel level, temperature) -- in effect, you can think of them as ammeters, whereas their senders, in turn, are variable resistors. Therefore, the accuracy or reliability of their indications depend on a constant voltage, so that the only variation in the circuit, and thus the only cause of changing current, is the varying resistance caused by high or low temperature or fuel level on their respective senders.

And because the system voltage in car can normally vary from a little over 14 volts to around 12 and a half volts, which is too variable to permit reasonably accurage gauges, your car has an aforementioned voltage regulator that provides (or it should provide) a near constant voltage -- sometimes this is called a "reference voltage" (although I'm not sure the terminology is quite right). The input to the regulator has to be greater than its output, so arbitrarily your car uses a 10.0-volt regulator.

Maybe your voltage regulator is faulty. One indication of a faulty regulator is that both the temperature and fuel level gauges will be quirky at the same time, since they rely on and share the same voltage regulator.

Good luck.

you did not say what year your car is BUT for argument sake on a 1990 non abs and on a 1992 with abs 240 car if you remove the cluster out of the car and grab the circular plastic connector with pin receptacles all around pin hole number 2 with the yellow harness wire out of it is the temp sensor wire.

a simple continuity test between the sensor end and harness end next to the cluster will tell you asap.

i suspect your problem is not that simple and lies in bad circuitry in the cluster board.

Hi,

Before doing anything else I would pull your cluster again and make sure your wire is on the right pins just to be on the safe side before purchasing anything.

Travis

look at the wire that connects to the sender on the block, should be the same color. I just went through this with my 93 240 and ended up having to get a new(used) circuit board. do you know anyone with a 240 that you can swap the cluster out with? just to eliminate that. I have a cluster from a 1990 laying around if you need any parts. check out the wire and sender on the block first.

I don't know what year your Brick is but the site below has wiring diagrams for several years.

http://www.volvowiringdiagrams.com/

Good Luck
Fred