What was found
CREW REPORTED- UPON TAKE OFF AND RETRACTING THE GEAR, RECEIVED LG AIR/GND FAIL AS WELL AS E1-2 REVERSE DISAGREE MESSAGES. LANDING GEAR INDICATED UP AND LOCKED. RAN THE QRH FOR BOTH MESSAGES AND DECIDED TO RETURN TO LAS. NO EMERGENCY DECLARED. MESSAGES DISAPPEARED UPON LANDING. CORR ACTION- FOUND MULTIPLE CONNECTIONS ON PROXIMITY SWITCHES TO BE SATURATED WITH DIRT AND DEBRIS. CLEANED AND TESTED ALL PROXIMITY SENSORS ON NLG/ RH MLG/ LH MLG. PERFORMED GEAR SWINGS CHECKED GOOD. PERFORMED CHECK FLIGHT NO DEFECTS NOTED.