I spoke to Joe yesterday, and he gave me more details of what he is trying to accomplish. He has a Sireno Siren Light, and a Sireno Siren Switch that he would like to install in his 1953 National Ambulance. I suggest that he use a Cole Hersee solenoid to control the siren by putting a stranded wire from the positive terminal on the starter solenoid to the Cole Hersee solenoid, and then another stranded wire to connect the Cole Hersee solenoid to the siren. The gauge of the wire will be determined by the type of motor that was used in the siren itself. I have seen motors as small as heater motors and as large as starters used in various sirens. For this 6 volt application, I would use the Cole Hersee model 24105 continuous duty SPST (single pole single throw) normally open solenoid. Normally open refers to how the contacts are in normal operation. Normally open means that the contact are not touching. This solenoid is rated for 85 continuous amps, so it is more than adequate for the current draw of any 6 volt siren. To operate this solenoid, you will pull a insulated 14 gauge stranded wire from one of the positive terminals in the fuse box and take it to the dash switch. It will then exit the dash switch and go to the single terminal on the solenoid that is located between the two leads that go to the starter and the siren. Since the wire is being sourced on the fused side of the fuse box it is not necessary to add any additional fusing. Always keep in mind that fuses are designed to protect the wiring, not the appliance, so you should never install a larger fuse than the circuit calls for.
As for the light on the front of the siren, you will also need to run a separate wire to operate that, and have that switched also. For this, I suggest that you use the Cole Hersee 5007 on/off, normally off single pull switch. This switch may need to be fused, depending on where you get the power source from. If there is a flasher mounted in the front of the siren light, you will wire to this flashers power terminal. If there is no flasher inside the siren light, and there are other flashing lights on the vehicle, then you can bypass this switching arrangement, and just wire the siren light directly to the flasher for the rest of the vehicle lights. Much of these instructions are generalized, and the specifics will be determined in the field after examining the type of siren light you have. If you have questions or require additional information, please don't hesitate to ask. Paul