1990 75hp Mariner - up trim not working

[turtle1173]

Hi all,
I just got this motor and am setting it up. Serial number is 0C281957. I've got down trim but no up. It doesn't click when button is depressed. If I bypass the up solenoid by connecting the two big wires it trims up. I then swapped the solenoids between up and down. No change. Down still works but not the up. Should I then be able to determine that the switch is faulty? I've checked all wires, connectors, and bolts. I even took the switch out of the controller to see if the wiring was frayed or cut. Wiring all looked good. Anything else I should check? If it is the switch, could someone help me get a part number? I've attached a pic of my controller.

Thank you for the help!

 

[oldman570]

Using a ohm meter, or a test light, to test the switch will tell if the switch is bad. It could be that the up wire from the control to the relay or solenoid is bad. Switching the wires on the switch it self will also tell if the switch or the wire is bad. New switches for the control can be bought at most local Merc dealers or online at several sites. Your controller looks to be a Commander 2000 series by Mercury Marine. JMO
Oldman570

 

[Texasmark]

Does your engine have a trim button on the side of the cowl, starboard side? If so, those switches are in parallel so if the engine one works your control switch as you suspected is bad or wiring to it. Would take the switch or a corroded connection as the culprit. You have a couple of screws staring at you on the front of the lever arm. Removing them should allow you to pull the cover and access the rear of the switch to ohm it out. Remember to disconnect the battery from the engine before you do that as the red center wire will be at 12v. You could just take a short wire and jump across to the blue which is up and see if it works. If so the switch is your smoking gun. That's an earlier model. Current models, which they sell here (having bought one) have the switch up where your hand rests and makes it real convenient for your thumb to punch it while you fingers are on the T lever.

Mark

 

[turtle1173]

Some interesting findings this afternoon, that I hope you all can help me make sense of. First, no, this motor was made right before they started putting trim switches on the engine.

Ok, i opened up the controller and all the wires really look good. All the connections are solid and there's some black stuff that seem to protect those. There's a little black plastic piece that houses the connectors that come from the harness to the switches. I opened that up and switched the connectors between the up and down. Hooked up the battery. When I push up, now the motor goes down. However pushing it down, results in it not going up. So my thinking is that it must be the blue/white up wire that goes to the up solenoid. So I start tracing the wire back to the engine. All the wiring looks good. However I can't see inside the controller and I can't see where the blue/white wire is inside a black sleeve from the solenoid to where it hooks to the trim harness. I dread if it's inside the controller. So I rigged up another wire to go from the solenoid to the harness.

Ok, what's confusing to me is that when I hook it up this way, the up trim button still doesn't work BUT the trailer button now trims the motor up. I Immediately switched the wires back and the trailer button didn't function, just like it didn't before.

So, where does that leave me? Up button switch works, when the wires are switched to the down trim. But up switch never works under regular conditions. Am I still looking at a blue/white wire issue in the harness? Switch?

Please impart some wisdom

Thank you for your help!

 

[Faztbullet]

That control box is set up for a engine with a trim limit switch which yours does not have,try tying the pur/wht to the blu/wht and see what happens...

 

[Faztbullet]

wiring

 

[turtle1173]

Awesome Faztbullet! That's exactly what I needed to know. Works great now. Thanks!

 

[Faztbullet]

Your welcome!!!