[RogerP6980]

We're having a problem getting the machine to fill for the wash cycle. I paid a service tech. $75 to diagnos, and he said the timer was bad. I replaced the timer with a new one, and the problem is still here. It has never failed to fill for the rinse cycle, the problem only shows up for the wash cycle. We have discovered that by switching the "LOAD SIZE" knob back & forth between the selections, it will usually fill. There have been a couple of times that it wouldn't, and we just gave up on it, then later we would try it again & it would be OK. I'm thinking it's either this 'LOAD SIZE' switch, or a valve hanging up (we have the typical Florida water that can build up in valves & seals). Any help would be appreciated.

[denman]

Well the timer was a good guess

Following is a manual for Whirlpool. Not for your specific unit but does have some good trouble shooting help
Free Appliance Repair Forum - Downloads

Are you using the same water temp for wash and rinse, if so a hanging/clogged valve will not be the problem. It does not know what cycle you are in.
You could remove your hoses and check some of them nave a screen washer which can clog up. While you have them off give them a good check especially the hot. The valves do have a screen built in on the input side. You can check this and clean/replace if needed. The valves can be taken apart to get at the screen if you have to. Do not run without a screen in, if a piece of dirt gets into the valve and holds it open a slow leak can end up being a flood.

Even the Load Size Switch which I assume is a pressure type water level switch does not make sense. It does not know wash from rinse. My guess is that the plastic line going up to the switch has gunk in it at the bottom and is doing weird things. You could try blowing into it OR pushing a wire down the tube, be careful though you do not want to put a hole in it OR replacing it.

Disconnect the plastic tubing going to the pressure switch, now will it fill for wash?
Put a piece of tubing on it blow in it, can you stop the filling?

In case you do not know how this switch works
Water rises in the plastic tube with the fill
Air is trapped in the tube
The rising water increases the air pressure in the tube
And this then triggers the switch at a preset point

Hope this helps