Dual trim pumps, one switch?
08-13-2014, 06:18 PM
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Dual trim pumps, one switch?
Hi all! Does anyone know if I can rewire to run both drives up and down with one of my existing switches in the throttles. (85 Mercruiser twin 350's with separate trim switches on the tops of the throttles) I tried searching some but wasn't finding it. Thanks
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08-13-2014, 07:17 PM
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Yes, you can. Are your throttle trim switches the only ones you have or is there additional switches on your dash? As long as the switch is rated for the current of 2 trim pump relays you could just splice the wires from the switch you don't want to use to the one you are using. The safest and easiest way to do this would be to add 2 12volt relays. Just wire the coil of the relays to be energized off the trim pump relay terminal of the pump controlled by the switch you want to use on your throttle. Then wire the contact side of each relay to the up/down relays on the other trim pump. This would isolate the switches and still let you use your other throttle switch if the outdrives get out of sync. Hope this makes sense. I can prob draw up a schematic if you need one to reference.
08-14-2014, 12:46 AM
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You can easily do it with the addition of a couple of diodes. You need the diodes because they only let the current flow one way. You need that so that you still have switches that work independently. You can get the diodes from Radio Shack for about $2. I can check on the ohm rating tomorrow at the shop if you need me to.
Eddie
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08-14-2014, 06:14 AM
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You can easily do it with the addition of a couple of diodes. You need the diodes because they only let the current flow one way. You need that so that you still have switches that work independently. You can get the diodes from Radio Shack for about $2. I can check on the ohm rating tomorrow at the shop if you need me to.
Eddie
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08-14-2014, 07:20 AM
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Diodes..=.. illuminated electronic diode...= LED's. Now you have experience with them. Think of a diode like a check valve. Fluid, or in diode's case electricity, can only flow one direction. For trim switches you just don't need diodes that light up 
