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Trim/tilt intermittently doesn't work

S

Swarlos

Regular Contributor
2000 30hp 2stroke Mercury. I've had trouble using the trim/tilt every now and then. Sometimes I can run the boat for hours and it works fine. Other times it will stop working for some reason I can't identify. When it does stop working it acts as though it's completely disconnected to electricity, no sound of any kind. It takes awhile, but eventually it will work fine again after it fails. It can take a day or more to work normally. When it fails it won't work from the controls at the helm or at the switch on the motor itself. Any ideas? Seems like something electrical.
 
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It hasn't failed while at dock as far as I can tell. It seems as though I need to run the boat in order to trigger the failure.
 
Up and down or one or the other. If one or the other swap relays and see if the problem follows the relay....could be pitted contacts within the relay. The fact that both stations work it or fail to work it tells you it's a relay or the trim motor....relay if only one direction is a problem, motor if both.
 
Don't forget to check for a loose connection on probably the power side. Since both switches are out if the problem is supply then it would likely be closer to the battery or fuse box, no further than the first switch.
 
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Ok, I'll have a look at it. I don't have an easy way of getting the boat out of the water. Can I work on this electrical stuff while standing in the water or am I likely to get zapped? I can always disconnect the battery anytime I'm looking at the connections and reconnect it, but it would be harder to test that way.
 
12 volts won't zap you, not enough voltage or amperage (don't try that with the ignition wires though, they have enough voltage to light up your life!). Find your power wires while it's as convenient as possible, dock or whatever, and use an inexpensive test light to see if voltage is available when the issue occurs. It helps if you have already checked things when it works so you know which wires should be hot. Check both the wire end and the connector it's plugged on to separately as that could be where the juice stops flowing. As noted above, said poor connection could just as easily be in or at a relay so pay attention to what you have and where it should be.
 
12 volts won't zap you, not enough voltage or amperage (don't try that with the ignition wires though, they have enough voltage to light up your life!). Find your power wires while it's as convenient as possible, dock or whatever, and use an inexpensive test light to see if voltage is available when the issue occurs. It helps if you have already checked things when it works so you know which wires should be hot. Check both the wire end and the connector it's plugged on to separately as that could be where the juice stops flowing. As noted above, said poor connection could just as easily be in or at a relay so pay attention to what you have and where it should be.
 
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One other thing, if you can't find anything right away and the trim fails on the water and if you can't test it right then try wiggling wires around it might fix the problem temporarily at least.
 
I'm a novice at this stuff. I tried to back off the manual release screw so I could tilt the engine up to see what was going on with the trim/tilt motor, but the manual release valve is made of plastic and it's very hard to back off. I'm afraid I'm going to break the plastic before I'll be able to move it. Any recommendations for how to proceed?
 
I see in your first post that there is a switch at the motor, can you tell if there is power at the switch? Test light time, make sure to ground to either the negative post of the battery or a wire that goes directly tothe battery.
 
No, the tilt isn't working currently. It may be that the intermittent failure is now constant. I have wiring diagrams in the service manual, but it's hard to translate those diagrams to what's actually on the motor. It's hard for me to distinguish which wires I should be testing.
 
Intermittent problems can be a bear, sometimes it actually helps if it goes ahead and quits. The easiest place to start is at The switch, do you have any power on any wire? There should be power coming in and only after you have pressed the switch will there be power on another line. There are two ways they can get up and down, they can use the switch to reverse the polarity electrically you know, pos/neg and then push the switch the other way and its neg/pos which reverses the operation of the motor or they could use two relays that would do the same thing, push the switch on way it activates one relay for up and push the switch the other way and you get down. All that means that there is likely to be 6 wires on the switch, power and ground plus 4 wires going to the motor or relays which ever way they wired it.
 
Since you have a wiring diagram look and see where power from the battery (or hopefully the fuse) goes, to the switch or to the motor so you know where to start.
 
Quick clarification question, there are two trim tilt switches (one on the motor and one at the throttle) and two relays. Is one relay for up on the trim/tilt motor and the other one for down, or does one relay work for each trim/tilt switch?
 
You would need one relay for up and one for down that would be operated from either switch. I have seen relays that incorporates both up and down in one housing but it seems that you have two separate ones. Check for power at the relays first.
 
Ok, thanks. I went and got the manual an hour after I posted that question. There's an up relay and a down relay, it looks like the switch at the throttle goes straight to the switch at the cowl, so that will make it a little easier.
 
That's right, both switches do exactly the same thing with the same relays, it's just two sets of wires. Look at it this way, if you can get one switch to work the other one should work also so concentrate on the easiest one and hopefully you wont have to do anything to the other one.
 
I was just looking back at the previous comments and realized that it was mentioned that a relay could be at fault but the odds of two relays going bad at the same time isn't going to happen so I am again thinking that the power going to the relays is most suspect. The motor is still possible but it would more likely blow a fuse than do nothing at all.
 
So I opened up the relays to have a look. Every wire is showing connectivity on the test light except for the two that run to the tilt motor (one from each relay). The relays are getting power and the switches when pressed are also showing connectivity. I would like to raise the engine so I can see what the wires look like going into the trim motor, but the manual release valve is quite stuck.
 
Let's look at the relay situation, relays have two circuits, one for the trigger and a second one to do the heavy lifting of engaging the .load in this case the motor. Their will be usually 4 wires at least one of which will be hot with a test light (best checked at the socket) relays commonly have a schematic of how their wired on the side or top with the hot for the motor labeled 30 and the one actually going to the motor as 87. The other two are the ones responsible for turning the relay on usually numbered 85 and 86. If you jumper the two main connectors (30/87 for the motor) then the motor should run. If it does then you know that the problem is in the switch circuit. The switch circuit at the plug will likely have one hot wire and the other is grounded by the switch (or the switch provides the power and the socket has the ground) that one needs to be checked with the relay installed but not quite pushed all of the way down so you can hopefully touch the two pins to see if things change when the switch is worked. See what you find and let us know.
 
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Trim Wiring Diagram.jpg
Here is a picture of the diagram. Red (positive to relays) and black (negative to relays) have connectivity regardless of switching. Green/White has connectivity when pushing down switch, Light Blue/White has connectivity when pushing up switch. Neither Green nor Blue have connectivity when switching up or down.

There are only two wires that go to the tilt motor, green and blue. One acts as positive and the other as ground depending on how the relays are switched. I don't think connecting them together is the answer, but I could jumper positive directly to either one to see if the motor works.

The wires have plastic couplers before connecting in to the relays. Are those couplers removable/reusable or do I have to cut them to disconnect the wires?
 
Ok, it seems that they are using 87a relays to make a flip flop circuit, some relays have only one power contact 87 these have two 87a which is connected with no power applied and 87 which is hot when applied. You are going to need to test with a test light or ground your volt meter to the battery or starter bolt, somewhere there is a good ground. The switches are supplying power to one relay or the other so see if light blue/white is hot when the switch is pushed up and the green/white is hot when pushed down. I am assuming that the fuse in the red wire has been checked.
 
Yes, I checked the fuse. It's ok.

Both light blue/white and green/white wires are working as intended when I use the switch, but I don't get anything at the green or blue wires.
 
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