Wiring a 3 wire trim/tilt pump to throttle handle switch

[Captndrydock]

I've recently installed a 1980 Chrysler 115 on my boat from an old junker. My old motor didn't have trim/tilt and this one does. I started to install it the way I took it apart and I'm now wondering if I'm replicating a poor wiring job.

I have 3 wires out of the pump to a connector. Then 8' of wiring harness to the throttle handle. At this point the harness is spliced and steps down to smaller gauge stranded wire. And from there attaches to the switch.

Is this correct? I assumed these older motors didn't use relays, but I haven't been able to find a wiring diagram for a 3 wire pump motor.

Any help is much appreciated!

 

[racerone]

I think some of those used a solenoid for the " trim up " function.

 

[Captndrydock]

I think some of those used a solenoid for the " trim up " function.

Thanks, I'll look into that!

 

[Captndrydock]

I think some of those used a solenoid for the " trim up " function.

My concern was the step down in wiring sizes. Seems like a long run and then to step down. I just found a photo of a new old stock handle and harness and it looks like it has the same kind of wire splice and I assume its stepping down in wire size. It would need to just to fit through the handle. It does work with a thin jumper wire....

 

[dingbat]

My concern was the step down in wiring sizes. Seems like a long run and then to step down. I just found a photo of a new old stock handle and harness and it looks like it has the same kind of wire splice and I assume its stepping down in wire size. It would need to just to fit through the handle. It does work with a thin jumper wire....

Wire size is a function of load over distance. Splicing a smaller diameter wire on to a larger wire equals the sum of the drops of both wire sizes and lengths.

 

[Captndrydock]

After consulting with AI, I've been enlightened about the direct wire setup. Kind of amazing to get this kind of answer from my search browser...

Yes, there is a legacy direct-wire setup for Chrysler/Force 3-wire systems. In this configuration, the high-amperage current for the pump travels directly through a heavy-duty switch in the throttle handle rather than using external solenoids or relays.
This was common on older models (pre-1980s) or systems categorized as "power tilt" rather than "power trim".

Legacy Direct-Wire Diagram
In this specific setup, you only need to manage four primary connections:

• Red Wire (Power): Connects from a 30A fused battery source directly to the center terminal of your throttle switch.
• Blue Wire (Up): Connects from the bottom terminal of the switch to the motor’s "Up" winding.
• Green Wire (Down): Connects from the top terminal of the switch to the motor’s "Down" winding.
• Black Wire (Ground): Connects the pump motor directly to the Battery Negative (-) or engine ground.

Key Identification Features:

• High-Amp Switch: The switch in your throttle handle must be a momentary (ON)-OFF-(ON) type rated for at least 20-30 amps.
• Wire Gauge: The harness wires are typically thick (10 or 12 gauge) to handle the high current without melting.
• Connector: The pump usually has a round or square 3-pin plug that matches the throttle harness.

 

[Scott Danforth]

the switch in the handle is operating the contactors which operate the motor.

no way to run motor wiring thru a switch small enough to make it fit into the binnacle handle

a 20-30 amp switch is going to be fairly hefty

I would use a pair of $2 VF4 relays

 

[Nordin]

As Scott says, you need to operate the T&T with to relays and control them from the switch in the remote control handle.

 

[Chris1956]

My '77 Merc used a solenoid on the up circuit only. The PTT control switch was pretty robust, and the wiring was heavier on the down circuit switch, so no solenoid was necessary.

 

[jerryjerry05]

In the old days: they didn't have a Trim up on the Chryslers/Forces.
The outboards that had T@T usually had a heavy duty switch on the dash and heavy wires from the switch to the pump and battery. Starting around 86 87 they started using relays so they could use the T@T in the shift handle.
If you have any wires that go down in size with a butt connector? that will probably be a HOTTTT spot when activated(don't bury that/them connectors in a loom or harness(fire hazard). To wire a 3 wire motor: simple: Red=battery. Blue(up) Greed (down) Minimum 10/12ga wire and a heavy duty switch.The mounting of the pump completes the ground, make sure it's clean no paint.

Good luck.