1985 Mercury Tilt/Trim not working

jjackson9209

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May 4, 2020
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Hey Guys, I dont know what else to do and am stuck. Here is what happend and what I have done. It is a 1985 Mercury 50hp and I think its a type b tilt/trim. It has a Quicksilver Control box.

Everythign has worked fine for 10 years But recently the up had been acting weird. I had to push the switch a few times to get it to engage and start going up. Then one day, the up would only engage for a few seconds then stop. I could lower it, and then press up again, wiggle the switch a little, etc. and it would start going up again. I did that a few times and then It stopped all together, up and down. So I thought switch was bad. I took the handle apart, and got to the switch, but I did NOT unplug the battery.

As i was messing with the switch, I made the wire connections inside the handle touch a few times, activating the trim to go up / down. So then I figured it was for sure the switch that was bad, because that was bypassing the switch, and the tilt trim worked. But then that stopped working as well.

I assumed I had blown a fuse. I checked the 20a fuse at the trim pump and it was fine. I also checked the fuse in the acutal motor and it was fine. I then assumed a solenoid had gone out. So i Bypassed those and put 12v directly to the green wire on the pump, and the motor went down, no problem. I put 12v to the blue wire, and the motor went up, no problem. So I ordered 2 new solenoids, put them in. Still bypassing the trim switch on the control handle by touching wires would not activate the trim motor. I installed a new trim switch that I ordered. Still will not activate the motor.

I put 12v jumper to the up solenoid, motor goes up just fine. Same with the down solenoid.

There is 12v of power from the battery, through the 90a fuse, to both solenoids, then from the red wire, through a 20a fuse, all the way to the wireharness. From there, there are 2 wires that go to each solenoid.

There is continuity in each wire from the switch all the way to the harness. I bypassed the trim limit switch, but put it back, just to eliminate that.

I have no idea what else to check or to do. The pump works fine. The solenoids work fine. I have a brand new switch. The wires seem ok.

The trim pump only has 4 wires, blue/white, green/white/, purple/white/ brown/white (It also obviously has red/black 12v wires. ) The wires go straight up to the control box.

The only thing I can think of is that there is a fuse somewhere I havent seen on a schematic or something??? Or could something be wrong with the wire harness at the trim pump?? That is the only part I can think of replacing because everything else is just wires that all seem to test fine for continuity. How does power get up to the control box so the switch can work and tell the solenoids to send power to the pump???

It seems like it HAS to be something EASY! I can get the motor to go up and down by bypassing all the wires and switches and just applying 12v to the motor or 12v to the solenoids. And all the wires seems fine. I have no idea what to do.
 

alldodge

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Mar 8, 2009
Messages
43,222
In many cases there is a connector between the handle and trim pump. Continuity will check out but there is not enough to pass the current needed to energize due to corrosion. Don't know if this is you issue by need to check

Basic trim wiring
Unable to upload diagram right now, site issue
 

jjackson9209

Recruit
Joined
May 4, 2020
Messages
2
OK Thanks. The 4 color wires go straight from the control box tilt trim switch, to the trim pump where 2 of them go into a male plug harness, one wire goes to the trim limit switch and the other one is unused.( I think it's for a trim level Guage or something. It's never been used.). The wires from the male plug harness, plug into the trim pump female harness. This female harness has 3 wires. One is 12v power with a fuse. One wire goes to the up solenoid. One goes to the down solenoid.

I do not see how power can make it up to the control box switch besides this connection. The male side of this connection, the spade plug that would plug into the female 12v part, is unused in the male side. So does 12v pass to the 2 wires on one of the other spade plugs inside this female harness? That's the only way I can see how power would make it up to the trim switch, in order for the trim switch to make connections and tell the solenoids to fire up. I just don't get it.

It's so simple. There's only a few wires. I can apply power directly to the motor and get it to work or apply power directly to either solenoid and get it to work. But I can figure out how to get the dang switch to work. OR even be able to just bypass the switch, and touch wires together and make it work. I feel like it has to be in the female harness connection on the trim pump. But does that sound right? Would the 12v of power cross to the trim wires going to the switch, INSIDE the female harness?

It's so frustrating because I'm sure this is just a $6 fix and I'm sitting out week after week because I can't figure it out!
 

alldodge

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Staff member
Joined
Mar 8, 2009
Messages
43,222
The trim in my Rinker had issues years ago and it turned out to be the male/female connector. I bypassed it and as been good ever since

You know the colors, red 12V, Blue up and green down
 
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