Over 80% of all 12V issues are the result of a poor/missing ground. Insure you have a clean, solid ground. An aside; always have the engine running when operating the jacks, as low voltage will cause problems.
2000 Winnebago Ultimate Freedom USQ40JD,
ISC 8.3 Cummins 350, Spartan MM Chassis. USA IN 1SG 11B5MX,Infantry retired;Good Sam Life member,FMCA." My fellow Americans, ask not what your country can do for you, ask what you can do for your country. John F. Kennedy