What can be used to clean the contacts on the Shark power module for our CTM HS 2800 power wheelchair? There are 2 red, 2 yellow & 2 green lights on this chair that flash once and go off and then come back on. What might be the problem when this happens?

This power wheelchair uses a Shark joystick control made by Dynamic. The connecting cable plugs into the back of the joystick control and can be unplugged by pulling back on the lock ring of the connector. Spray electrical contact cleaner onto both the plug and the joystick cable receptacle.
Follow the cable down to the base and check for cuts, nick or pinches and repeat at the base connector. To get to the power module you need to remove the seat and cover for the base. The controller should have 5 connectors plugged into it. One is the power connector, one is the right motor, one is the left motor, one for the joystick plug, one for the charger. Remove these connectors one at a time, spray clean the contacts and plug back in. Inspect these connections on both sides and be certain the contacts are shiny.
A 6 bar flash indicates that there is a right park brake fault. Work the right brake release lever up and down several times and see if this clears the fault. Do the same for the left brake. If you have cleaned the right motor plug at the controller by disconnecting it you can use a digital voltmeter to test the brake. The 2 small wires to the plug are the brake wires and should read 40 to 60 ohms on your meter. If the brake solenoid reads open or shorted your brake is burnt out. The two easiest things to try are moving the brake levers and spray clean all the contacts. The test/replacement of these parts requires a qualified technician. Hope this helps.