2017 Mercury 150 tilt/trim problem (location of relays)

[MrTim]

I've searched the forums and don't see anything that suggests location of the tilt/trim relays for my 2017 Mercury 150.
The Mercury parts diagram for my model shows the location of 4 relays that I assume are under the cover of the electrical box on the port side. See diagram below.
Of the 4 relays, which ones are the tilt/trim? What do the other relays control?

The problem I'm having that has me interested in tilt/trim relays is that when I came back from a ride today and put the boat (2017 Tracker Targa 20) on the boat lift I could hear the trim motor running continuously. The only way I could stop the trim motor from running was to disconnect the main battery cable. I suspect that that the motor was running "down" as the motor remained in the down position. Upon further troubleshooting, I noticed that I could interrupt the motor when pushing the "up" on the trim switch on the throttle. That makes sense as the two relays work together to swap Positive/Negative to the trim motor leads.

I'm hoping its simply a relay that is stuck. Or at least its the most likely thing to try. The model of tracker boat I have has a three tilt/trim switches, one on the throttle, on at the bow, and one on the cowling. The boat is always covered with canvas and on my boat dock has a roof so I don't think that any of the switches is damaged by water infiltration. However, once I know which relays are for tilt/trim I may be able to measure voltage going to the relay to further test.

Again, if anyone knows what each of the four relays do, I sure would appreciate that info.

Thanks, in advance and Happy New Year !!!



According

 

[QBhoy]

Hi,
Having a similar age and very similar engine, the 115. I can tell you that these can have a couple of issues with the trim system.
Firstly is the engine mounted trim switch activating on its own. You can disconnect this to fault find
secondly is that some (including mine) have an issue at the remotes. The trim wires running from the thumb switch down the handle of the throttle arm, can get pinched in there and short out. They can also get pinched through, if the wires have been jammed by the get and throttle mechanism inside the box itself.
lastly is that some set up's have an additional and unused bow trim wiring system. This can sit hidden from view in the bottom of the boat somewhere and can occasionally short out against other things or even bilge water, along the way somewhere.
Alternatively, you could be correct in thinking it is the relay. There are a few relays on these. for trim, start and main power.
I would start with the engine mounted trim switch, should I be a betting man.

 

[MrTim]

Thanks for the info, I'll disconnect the t/t switch in the cowling, that is a great suggestion and I will do that, much appreciated!

What I was asking for is what do the 4 relays control? According to the attached diagram, there appears to be 4 relays. I was asking is what each of the 4 relays do. I know 2 of them are for tilt/trim, but which ones? And what do the others do? And of the identified relays, which one is at the top and which one is at the bottom, as well as those between?

Thanks in advance for any replys...

 

[QBhoy]

Thanks for the info, I'll disconnect the t/t switch in the cowling, that is a great suggestion and I will do that, much appreciated!

What I was asking for is what do the 4 relays control? According to the attached diagram, there appears to be 4 relays. I was asking is what each of the 4 relays do. I know 2 of them are for tilt/trim, but which ones? And what do the others do? And of the identified relays, which one is at the top and which one is at the bottom, as well as those between?

Thanks in advance for any replys...

the other two are for start relay and main power relay.
The trim relays are easy to identify. Follow the blue and green wires from the trim pump, which come up through a grommet in the lower cowling. or the blue and green thinner wires from the trim switches.
If it helps, they can be tricky to remove, from their mounting brackets. You will need a delicate touch with a flat blade screwdriver, to push the wee tab that allows you to slide them up and off the mount. All of these relays can be tested with a meter. From memory, they should all test at around 85 ohms across two of the pins...give or take a tolerance of a few ohms. Don't take my word for it though, check or look this up yourself.
If you find yourself having to go as far as the relays and you are struggling, let me know. I will send you some details from my manual for the 115. Very similar set up and shared components. Odds on to be the trim switch on the engine I would think though. or a related loose end elsewhere on the trim wiring along the route of the harness.
There are two multi plugs lying in the lower cowling somewhere near the front of the engine. one from the engine trim switch will be obvious and very local to the switch itself. Also look out for any trim calibration wires causing issue too. Orange wire is one of them.
Anyway, once you get one or both trim plugs opened up, you can easily and very quickly put a meter across things. This will tell you if the switch is the issue or alternatively, an issue on the power side of the system. Again, blue and green wires are what you are looking for. Look for a loose ended or dangling blue wire somewhere in the bilge or up near throttle too. If this is shorting or contacting water, it can cause issues. You might have a blue and a green wire with a weather cap on each, loose ended up at the throttle control box. Make sure these aren't pinched or compromised somewhere. But honestly don't think you will even need to look that far into it, after a quick look at the engine end, regarding the wiring there at switch.
Good luck

 

[MrTim]

OBhoy, thanks again, much appreciated. The tip on using the blue/green wires to identify the relays in question will help.

Its a cold morning here in TN, so I may need to wait a day or two for it to warm up a bit.
The first thing I'll try is disconnecting the cowl-mounted switch as that's easy.
The second will be to remove the cover on the power center and test out the relays. It appears to be fastened with 3 bolts. I'm cautious on doing that as I'll be working while the boat is on the lift above water. I have a relay tester that I've use on some electrical project. I can also measure the voltage going to the coil terminals of the relays to see if the trim switch on the bow or throttle are stuck.

Friday temperatures will be in the mid-40s and I'll dig into the problem then and will update with progress.

Again, thanks so much for the info. These forums are so useful.

Tim

 

[QBhoy]

OBhoy, thanks again, much appreciated. The tip on using the blue/green wires to identify the relays in question will help.

Its a cold morning here in TN, so I may need to wait a day or two for it to warm up a bit.
The first thing I'll try is disconnecting the cowl-mounted switch as that's easy.
The second will be to remove the cover on the power center and test out the relays. It appears to be fastened with 3 bolts. I'm cautious on doing that as I'll be working while the boat is on the lift above water. I have a relay tester that I've use on some electrical project. I can also measure the voltage going to the coil terminals of the relays to see if the trim switch on the bow or throttle are stuck.

Friday temperatures will be in the mid-40s and I'll dig into the problem then and will update with progress.

Again, thanks so much for the info. These forums are so useful.

Tim

Just on the off chance and going Jack to what I was saying about up at the remotes. If you find that it’s not from relays and points at an issue that’s maybe coming from the throttle trim side of things (if unplugging the engine switch doesn’t stop it and alternatively the other plug disconnected for throttle trim does), then take the remote box off the side panel and check the trim wires (blue and green and a red or black) are definitely going through the wee hole they are meant to on the back of the box and between the two removable panels there. Mine wasn’t and was jamming. Caused the wires to be exposed and causing issues. I then also found that inside the wires had worn through the insulation at two other places. Inside the throttle arm itself and also where it had been getting jammed on the throttle mechanism gear inside too. Was shorting out there too.
Also whilst you are there, you can check the two spare wires that hang loose from the throttle remote box. Think they are for a bow switch function. Blue and green wires that should be capped off with a weather protective end cap. They may be hidden down the side and shorting or in water somewhere.
Back at the engine, check the secondary positive power post on the front of the engine that lots of power wires use. Including the relays. Make sure all connections are good. As mentioned earlier too..check the trim calibration wires aren’t hanging in oil or water in the. Bottom of the casing too. Or even that the trim switch plugs aren’t doing the same.
But all that aside, I think you’re likely going to find that your engine switch is bad.

 

[MrTim]

Damn..... the problem went away. Intermittent problems are tough to diagnose. The temp got above 40 this afternoon so I went down to the boat to further diagnose the problem. When I noticed the problem a few days ago the only way I could get the trim motor to stop was to disconnect the main battery cable. Today, first thing I did was to connect the main battery cable and expected the trim motor to run by itself, but it didn't everything seemed normal.
I used all three trim switches (bow, throttle, cowl) many times each and none seemed to stick or keep the trim motor operating when released.
I did see the connector for the cowl-mounted trim switch and it was dry. I unplugged and reconnected the cable to the cowl switch. The cable will be real easy to disconnect if/when the problem returns.
I looked on line and the cowl switch is only $48 so I may proactively replace it to eliminate that switch. Its the only switch that could likely have water splash on it, possibly when boat moving in reverse, but everything looked dry as a bone both today and the other day while the trim motor was stuck on..

Nest Monday's weather forecast calls for upper 40s so I'll take it out for a couple of hours then and see if the problem returns. If it happens again I'll disconnect the cowl switch and I believe I can easily get to the front trim switch as well. That would at least eliminate those switches as the cause.

QBhoy, thanks again for all the info, I am very appreciative of the info you provided.

Until Monday.........

Tim

 

[QBhoy]

Damn..... the problem went away. Intermittent problems are tough to diagnose. The temp got above 40 this afternoon so I went down to the boat to further diagnose the problem. When I noticed the problem a few days ago the only way I could get the trim motor to stop was to disconnect the main battery cable. Today, first thing I did was to connect the main battery cable and expected the trim motor to run by itself, but it didn't everything seemed normal.
I used all three trim switches (bow, throttle, cowl) many times each and none seemed to stick or keep the trim motor operating when released.
I did see the connector for the cowl-mounted trim switch and it was dry. I unplugged and reconnected the cable to the cowl switch. The cable will be real easy to disconnect if/when the problem returns.
I looked on line and the cowl switch is only $48 so I may proactively replace it to eliminate that switch. Its the only switch that could likely have water splash on it, possibly when boat moving in reverse, but everything looked dry as a bone both today and the other day while the trim motor was stuck on..

Nest Monday's weather forecast calls for upper 40s so I'll take it out for a couple of hours then and see if the problem returns. If it happens again I'll disconnect the cowl switch and I believe I can easily get to the front trim switch as well. That would at least eliminate those switches as the cause.

QBhoy, thanks again for all the info, I am very appreciative of the info you provided.

Until Monday.........

Tim

No worries Tim. Best of luck…you’ll be well versed by now, should it arise again.
All the best, Allan.