Battery Boost Solenoid; Relays - Monaco Cayman 2005 Owner's Manual

The battery boost solenoid is located in the battery compartment. A
dash-mounted momentary switch is added to provide a BOOST for the
chassis batteries from the house batteries in case the chassis batteries are
weak and will not crank the engine.
When traveling, the solenoid is engaged, charging both the house and
chassis batteries at the same rate of voltage.
The motorhome uses various relays to operate electrical equipment
such as lights and motors. If a relay needs to be replaced, carefully
record the location of each wire and all markings or labels.
Relays can look the same in appearance, but differ in function.
Note that on the side of the relay is a schematic drawing identifying if
the relay is 87 or 87a relay. These current ratings differ, and if mixed,
will create problems. Ensure the replacement relay is of the current
rating to assure proper operation.
Another indicator to the type of relay is the post or legs. Turn the
relay over and look at the post.
Note the differences between the numbered posts:
1. The 30 post is the incoming fuse and/or breaker power.
Some relay applications supply power to the 30 post. Some
use it for ground. The 30 post can be used
many different ways.
2. The 85 post is one side of the coil, tripped
different ways.
3. The 86 post is the opposite side of the coil,
tripped different ways.
4. The 87 posts are not common to the 30
post until the relay is tripped. When the
relay trips, both 87 posts are common to
the 30 post.
5. Using an 87a relay, the 30 post and the 87a
post are common. When the coil is tripped,
the 87a post becomes inactive and the 30
post becomes common to the 87 post located
on the outside of the relay.
Cayman 2005

Battery Boost Solenoid

12 Volt DC
Relay
30
Electrical Systems - Chassis --- Section 9
060216h

Relays

080406
080405b
080405c
293