Service and Repair Manual September 2015Ground Controls52 S-80 • S-85 • S-80X Part No. 1269074Ground C ontrols6-1 C ontrol Rel ays6-1Control RelaysRelays used for single function switching are singlepole double throw (SPDT) relays.How to Test a Single Pole DoubleThrow RelayElectrocution/burn hazard.Contact with electrically chargedcircuits could result in death orserious injury. Remove all rings,watches and other jewelry.Electrocution/burn hazard. Contact with electricallycharged circuits could result in death or seriousinjury. Remove all rings, watches and otherjewelry.1 Tag and disconnect all the wiring from therelay to be tested.2 Connect the leads from an ohmmeter orcontinuity tester to each terminal combinationand check for continuity. Terminals 85 and86 represent the coil and should not be testedin any other combination.Test Desired resultterminal 85 to 86 with resistor 75 to 85Ωterminal 87 to 87a and 30 no continuity(infinite Ω)terminal 87a to 30 continuity(zero Ω)3 Connect 12V DC to terminal 85 and a groundwire to terminal 86, then test the followingterminal combinations.Test Desired resultterminal 87 to 87a and 30 no continuity(infinite Ω)terminal 87 to 30 continuity(zero Ω)• terminal no. 87a - N.C.• terminal no. 85 - coil negative (-)• terminal no. 30 - common• terminal no. 86 - coil positive (+)• terminal no. 87 - N.O.Control Relay Schematic
