This discussion is instead of further hijacking the solor panal demise
Sailors- Not sure what you mean by sealed box or cover (I know WRV had a formed battery cover in years past but thought it was discontinued B4 05 models). However, as to testing the solenoid:
1) locate charging solenoid on back wall of batt compartment. Your OEM solenoid was probably silver in color, and made by Cole-Hersee, with two large studs on either side, and two smaller studs facing forward at an angle; you might have a different one now. The two smalls are the activator connections; when 12V is present across these the solenoid activates to close large contacts inside & complete the circuit between the fat cables on each side, and thereby send charging current to the chassis batteries.
2) disconnect the right hand fat cable. Be careful not to touch any metal with it as it is directly connected to the chassis batts and will cause an invigorating short (sparks fly, stuff gets burned, etc.). I have a piece of heavy tape ready to wrap the cable end when I remove it, so if it bends in an unplanned way it is insulated & nothing bad happens. This allows you to test the solenoid's internal contacts w/out back-feed thru the rest of the charging system.
3) disconnect the left hand small cable on the front facing studs. This will deny the solenoid its activation current.
4) using an ohm meter set to ohms x 1000 (available @ Radio Shack for about $20 for a good one; I prefer one w/a needle dial instead of digital for this) touch one lead to each large stud on the solenoid (or better still- use meter leads w/alligator clips for a solid, uniform, no-hands grip; also available @ Radio Shack for their meters). The needle shouldn't move (reading infinity). If it does there may be internal leakage of current across these studs and solenoid is probably troublesome at least.
5) using a spare wire lead, run from one of the red cable studs on the house batts near the solenoid to the left small stud on solenoid. Alligator clips are good here to maintain a continuous contact w/no hands required. You should hear the solenoid thump when you connect 12V to the small stud. Now measure the ohms across the large studs again. write down the reading.
6) repeat #5 several times. If you always get identical readings, solenoid is probably good. If the readings vary, then the contacts inside are probably burned and make slightly different contact each time; time for a new solenoid.