91 Bird turn-signal switch interrmittent

As title says, turn-signal with wipers goes intermittent--usually goes out after car has been driven for awhile. When out-no flash on the dash and no turn-signals on outside working. Tried spraying with contact cleaner to no avail. Too scared to use WD-40, etc. I know when these switches go out completely the switch feels sloppy and loose, but this one still feels tight. Mechanic says there is no flasher-type button to check. Finding good deals on switch for 94-97, but the one for 91 seems very expensive. If I take the switch out, anyway to tell if connections just need cleaned. Thanks in advance.

Go to your library and ask for the Mitchell Electrical manual for your year car and you can see which wires go where in the switch from the connector. Then you use an ohmeter to check the continuity between pins in the connector for each part of the circuit.