Battery Switch?

[Golfdad75]

For the last four years or so my keysometimes will not turn the engine over. Either it will on subsequent tries or I go down and switch the battery to all. But if I switch it to the house battery only it does the trick.When I turn the battery switch it never fails. Lately it has happening more and more and I want to fix it, I am thinking my switch is the problem. Any thoughts

[Dave Neptune]

G, check the connections and grounds on the batteries as well as the connections to and from the switch.

With some help you could check for voltage drops that could well point to the switch. They do go bad from time to time after many years of service.

The key switch is also suspect if your start and/or house battery are week too.

Dave Neptune

[sastanley]

GD75, Any connection is suspect, but if one battery works and all or the other doesn't, focus on the bad battery connections, as Dave noted.

Just need to spend an afternoon cleaning everything up! You can get cheap CRC electrical cleaners in a spray can from Lowe's or Home Depot. Physical scraping with a brass brush does not hurt either to remove any corrosion. I've found that good solid connections tend to not corrode as much as those that might be loose.

[Al Schober]

GD,
When you get your connections clean, put a little silicone grease on them when you make them up. It will keep the connections clean longer by keeping moisture out of the interface. I use Dow Corning #111 - a 5 oz tube from McMaster will last a lifetime.
A good check of your A/B switch is to watch your cabin lights as you cycle the switch. If the lights flicker, the switch is going bad. If the engine is running, a bad A/B switch can fry your alternator.