Trim up doesn't work, but trailer switch does

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JASinIL2006

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I returned from a day on the river Sunday, during which my boat performed without any problem. When we were putting away the boat into the garage the next night, I was having my son lower the outdrive to relieve pressure on the bellows. In order to raise the trailer tongue to get the bow higher in the air, I asked him to raise the drive a bit. It did not respond to the Up trim switch (we have a rocker switch on the throttle handle). The down trim switch continued to work to lower the drive, and the trailer switch also continue to work to raise the drive. When the up trim switch is pressed, there is no noise, no click, no pump hum, etc. It just doesn't work.

I consulted my Mercruiser manual (I have a '97 Mag 350 with Alpha One Gen II drive in a Larson 186 bowrider) and it suggests I test and clean the connectors between the trim limit switch and the trim up/down switch. From the diagram, it looks like the connectors should be somewhere closer to the drive unit than the throttle unit, but unfortunately, I can't seem to find anything that looks like connectors. There is a large bundle of wires entering the engine compartment from the front of the boat, and I cannot see where the connectors might be.

Before I clip the zip ties holding this big bundle of wires together so I can trace back the individual wires to see if I can find the connectors, or try to trace back from the trim control wiring harness connector, I thought I'd see if anyone had any thoughts on where I might look. (Also, if you have thoughts on whether my diagnosis is on track, those would be welcome, too.)

Thanks!

Jim
 

stonyloam

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Re: Trim up doesn't work, but trailer switch does

Do not clip anything! Go to the transom and look for two black wires coming from the transom plate (behind the engine) and going into two connectors, one with purple/white wire and one with two blue/white wires. Those are the trim limit switch wires. To test, unplug the black wires and take a short piece and jumper between the two connectors. Try the trim, if it works then you have a problem with the trim limit switch circuit, either the wires or the switch itself. Let us know what you find and we will work from there.
 

kd7isf

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Re: Trim up doesn't work, but trailer switch does

How high are you trying to "TILT" the drive with the "TRIM" switch?

The "trailer" button is the up TILT button. The ONLY up TILT button.

The up button on the rocker switch is the up TRIM button.

TILT = raise the drive all the way up such as when you have the boat on a trailer and you want to drag it down the road.

TRIM = adjust the drive angle when driving the boat in the water.

The up TRIM button only allows the drive to go up to the maximum safe angle for operation.
-This is what the trim limit switch is for
-This is done so your drive doesn't self destruct when you hit the gas.....


It sounds like your drive is working like it should..

Hope this helps....
 

JASinIL2006

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Re: Trim up doesn't work, but trailer switch does

The trim button is not functioning correctly. Trim down works fine. Trim up does not work no matter the position of the drive. Even with the drive fully lowered, the trim up switch does nothing. The tilt function, which corresponds to our "trailer" switch function, is working as it nrmally does.

Stonyloam, I'll see if I can find the wires and do as you direct, and then I'll report back. Thanks!
 

tpenfield

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Re: Trim up doesn't work, but trailer switch does

the trim sender and trim limit switch wiring comes in through the transom assembly and connects near the rear of the engine. It sounds like the limit switch may have a broken wire or is not connected.

Here is a picture of where the wires come through the transom assembly, so you can start there to trace them out. Notice that they are just below the steering arm.

IMG_0520.jpg
 

theBrownskull

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Re: Trim up doesn't work, but trailer switch does

Tpenfield,

The same happened to my 1997 Starcraft last summer. I found the connections to the hydraulic pump were fine. The problem was in wiring to switch at the throttle. If the pump tests ok I would check the wiring by the throttle because they get pinched and break. You will have to take the cover off on the control.
 

theBrownskull

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Re: Trim up doesn't work, but trailer switch does

Tpenfield

Sorry the above post was for JAsinIL2006.
 

stonyloam

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Re: Trim up doesn't work, but trailer switch does

I would check the wiring by the throttle because they get pinched and break. You will have to take the cover off on the control.

Jumpering the connectors will check the control wires, if it works your wires are OK.
 

achris

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Re: Trim up doesn't work, but trailer switch does

ok.. '97. Make yourself a small jumper wire. About 2" long with a male bullet on each end... Now find the connections that the trim limit switch wires plug into. They'll be in the trim pump wiring harness (the one that leads up to the control box), but right near the trim pump. You're looking for one wire that is Purple/White and the other connector has 2 wires, Blu/wht.... Pull the 2 black wires out of these coloured wires and plug the jumper you made in.... If the trim switch on the controls now works, the problem is the trim limit switch and/or its wiring...

Chri.......
 

JASinIL2006

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Re: Trim up doesn't work, but trailer switch does

Too dern hot here in Illinois today to be hanging out in the garage trying to find wires in the engine compartment, and I'll be away from the boat for a week or so. This will have to sit for a while, but I'll report back when I can get on it again.
 

wvit1001

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Re: Trim up doesn't work, but trailer switch does

Too dern hot here in Illinois today to be hanging out in the garage trying to find wires in the engine compartment, and I'll be away from the boat for a week or so. This will have to sit for a while, but I'll report back when I can get on it again.



Look up closer to the throttle handle. Mine was doing that and I found the connections were loose back behind the throttle handle. There should be a connector right behind where the handle mounts to the side panel.
 

stonyloam

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Re: Trim up doesn't work, but trailer switch does

Look up closer to the throttle handle. Mine was doing that and I found the connections were loose back behind the throttle handle. There should be a connector right behind where the handle mounts to the side panel.

Do that IF the jumper wire does not work. You first need to isolate the problem to either the control handle switch or the trim limit circuit, the jumper test will do that.
 

TestDriveTech

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I am having the same issue with my ‘93 Celebrity with a 454 Mercruiser Alpha 1 Outdrive. I’ve read through the replies here and need to know do you jump the two black wires together or do you use the jumper wire on the connectors on the solenoid position switch on the transom?
 

achris

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7 year old thread. Please read the forum rules and guidelines. Unless you are the original poster, no posts to threads more than 90 days old.

Thread closed....
 
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