Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 284Get this manual
Electrical System Troubleshooting GENERAL CHECKS
3Check that plug-i connectors are fully engaged4Make certai battery is fully cha rged
Before troubleshooting the Power Trim electrical system, check the followi ng:
1Check for disconnected wi res2Make certain all con nections are tig ht and corroRefer to the preceding two wiri ng diagra ms for connection points when troubleshooting the electrical system(Connection points are specified by nu mber
sion free
Troubleshooting the "Trailer" Circuit (When "Up" Circuit Is OK)