Help! Trim system issue

[nate_gig_harbor]

2001 Bayliner Capri 192 with a new (in 2010) mercrusier 4.3 with the Alpha One outdrive

3 weeks ago went to raise the motor and nothing. Up/Trailer switch not working, down direction was 'clicking' intermittently.
Checked the pump motor, solenoids and things looked like they needed a refresh so I replaced both the up and down solenoids, cleaned all connections with sandpaper, replaced the 20 amp fuse and checked the voltages and continuity of all solenoids and switches. Since then now none of the trim switches are working, not even the trailer button.

- Can manually jump solenoids and raise/lower motor. Could do this before and after replacing both solenoids.
- Pulled wiring harness connector and tested leads and am getting continuity on switch (using Ohm meter) for down direction and trailer switch, no continuity on up switch at all.
- no more clicking on the down direction.

Feels like this is a trim limit switch problem but would that have cause the 'down' switch to fail as well? Or if the up/down switch on my control unit went bad, as indicated by the lack of continuity on the 'up' switch, would that cause 'down' and the trailer button to stop working as well?

 

[wannabewelder]

We had this problem. I took apart the trim motor and cleaned it but you will find special brushes inside them called "constant force" spring holders. I dealt with repairing those but it wasn't the issue. BTW Merc wont sell kits, just whole motors which is why I repair them.
In the relay system you are hearing clicks and finding power BUT while you may show power looking like it works you also need to reverse polarity and check for ground. A standard relay needs 2 + and 2- to operate. These relays ground through the opposite relay. In other words, the up relay when energized has a contact that closes and puts power to the down relay that "should" ground and vise versa. If it doesn't ground it won't work. If you cut the relay apart, you may see the point is corroded (it is a 2 way point) positive polarity in 1 direction and neg when de-energized.
Common issue. Now, these are standard relays, every car made up till 2000 used them so now it's a quality issue. I used fuel pump relays off 89 S-10 trucks that are used, Toyota cars etc. The pins should be 0.250" and the diagram on the side of the relay should show the same numbers and position. With relays, quality is dependant on silver points so I use USED automotive figuring if I got 300,000 miles on an electric pump the relay must be good.
The click you are hearing is the primary side of the relay closing BUT the secondary is likely not grounding.
A simple way if you don't know how to read the diagram is to look for BIG wires. The primary side (control) is the lighter gauge and the load side is heavier. It seems to me that Merc used all the same wire but this is how you determine load side. So now you need 2 hot terminals on your test light and then reverse polarity and look for 2 grounds (or) stick a cotter pin in the hot side, connect test light to it and probe the other terminals TO CHECK GROUND. It seems to me those are 5 pin relays.
Now, in a single relay system I would jump the big + to big - PROVIDED your ground is good and if the motor turns ie fuel , fan, you know the relay is shot. In this scenario that won't likely work as I suspect the relays are BOTH shot.

 

[wannabewelder]

The up down switches "should" be wired in parallel so provided you checked for power continuity there I would go back to relay grounds.

 

[nate_gig_harbor]

Just confirming, you guys are using the term relay and solenoid interchangeably here?

 

[wannabewelder]

I am not a marine mechanic so I don't have a visual of what you are looking at but solenoids and relays are very similar. Solenoids use a metal plunger that is magnetized. Solenoids are usually controlled by relays to save weight by downsizing wire gauge.

 

[wannabewelder]

These should be DC motors and turn in both directions or is there a hydraulic valve that opens and closes?
Go to the solenoid small wire and see if you have power when you hit the switch, if not it's the switch/ control ckt.

 

[wannabewelder]

You were also unclear, is the continuity problem IN the switch itself or in the wiring?

 

[Bt Doctur]

The mercruiser trim pump is bi-directional with 2 windings the blue wire is up ,the green wire is down. The solenoids need a positive and ground on the small posts to operate. The small blue wire to the up solenoid and the small green wire to the down solenoid, the other 2 small posts are jumpered and go to the same ground bolt that the main neg feed goes to.

If jumping the large lugs operate the motor in both directions ,then check the wires and grounds on the small posts
Use a jumper from the + gattery to the small posts. If the solenoid operates its good and you have a main 20 fuse problem or a wiring to control box problem or a corroded harness plug.

 

[Bt Doctur]

 

[nate_gig_harbor]

The continuity problem is in the switch only. When I disconnect the control cable harness and test resistance when pressing the up/down/trailer buttons on the handle, the 'up' switch shows no continuity while the others do. Given this circuit goes through the trim limit switch, I was curious if that was the issue. but with the down and trailer buttons not working either, I was (am) pretty stumped since the grounds all seem good. That is a good suggestion to manually jump the small terminals to test the solenoids, but given I just replaced both of them new, i think they will be ok. one thing I didnt do was clean the wiring harness male/female connectors although they dont look too bad

 

[wannabewelder]

From the diagram above it's a pretty simple system. If continuity issue is confined inside the switch then there is your answer. On the battery cables it is sometimes good to check for voltage drop with a dvom.

 

[nate_gig_harbor]

Thanks wannabewelder ! I just couldnt really get my head around why good continuity on down/trailer button wasnt working if it was isolated to the switch. i.e. does a faulty 'up' switch break the other functionality?

 

[wannabewelder]

I don't know if I helped you yet. You have to Ohm out each switch. My last boat had 2 switches that were wired in parallel. So use a test light and make sure you aren't buying parts you don't need. You checked the solenoids and pumps and that seems ok which is the big money. On a budget you could rig up a SPDT switch for $3 that would fix that. I think the proper switches are $20.

 

[wannabewelder]

Thanks wannabewelder ! I just couldnt really get my head around why good continuity on down/trailer button wasnt working if it was isolated to the switch. i.e. does a faulty 'up' switch break the other functionality?

This depends on how the ckt is wired. Go to pump and put test light clip on green wire and other end on blue wire. Hit switch. Does it light up?
Hit switch other way. Does it light up? If no, put test light clip on black wire and probe blue/ green. Y/N?
Then put test light clip on red BATT wire and do the same thing again. Y/N?

Scenerio 1, you checked for power in primary side.
Scenerio 2 you checked for power primary side.
Scenerio 3 you checked grounding.
If none of these work go to switch.
Check 12V +
Then check 12V operation to blue/ green or ohm switch. If these llight up at the sw but not the sol. then possibly broken wire. From your description I say mechanical sw, but I see other clues every time I read it.....

I like scenario 1 because it easily identifies if the ckt you are working on grounds vs an external ground which is a false positive.
Don't rule out a broken wire.
You can ohm a wire and have continuity, you can volt a wire and have the same but the amperage may create R under load so then you would V drop test..
Hopefully this helps somebody.

 

[achris]

Check the 20A fuse, and the connections right end... And no, lack of continuity in the up circuit should not affect the down circuit. If you're concerned the limit switch is causing problems, just remove the connectors and put a jumper in place. That will restore continuity to the up circuit.

 

[wannabewelder]

I have had fuses look good with a test light and be rotted on the back side of wire terminal.

 

[nate_gig_harbor]

FOLLOW UP! SOLVED

I threw in the towel and took her to a local shop after not being able to diagnose the problem.

Even though I tested for voltage at the power bus through the 110AMP fuse to ground, and always had 12v, and then tested for voltage across the solenoid terminals both with the switch engaged and not engaged. it turns out the 110AMP fuse was failing under load ONLY.

I, instead, followed the red-herring of control switching/wiring/fusing when the solenoid wouldnt engage and assumed that if voltage was passing through a fuse when not under load that the fuse wasnt faulty.

LESSON LEARNED!!! Replace the $28 part even if it tests OK https://www.wholesalemarine.com/fus...MIjKHUkOuV3QIVlMBkCh1HkQqeEAQYASABEgK5nvD_BwE

Good news is the bill was only $200, so could have been worse.

 

[achris]

... and assumed that if voltage was passing through a fuse when not under load that the fuse wasnt faulty.....

Welcome to 99.9% of the population...

That's a nasty one!

Chris......

 

[wannabewelder]

This is how we learn.
For a fuse to fail under load you would need to have resistance. Is this some type of special fuse? The resistance to do that should "blow" the fuse. V:IxR. Let's say the tech sanded down the contacts and replaced the fuse would make more sense. My wife's car would not start. I sanded down the batt terminals and it then worked. The R was in the corrosion. Fuse links do not create Enough R to restrict A without opening.
I thought I had posted to check for a voltage drop with a doom and how to jump the ckt to identify the problem. Glad you got it worked out, but it sounds like the bs' you for $200.

 

[wannabewelder]

My apprentice was in trade school and came in with his text book. There is a multiple choice question about a light bulb that doesn't light up and a 1.5V reading on a 12V ckt. I failed to answer correctly as the textbook answer is faulty ground. I sent a 12V build and a 1.5V battery back with him and asked why a 12V bulb glows dimly. The teacher conceded that electricity did in fact flow through the bulb. There was a few other options like short after a load and ahead of another which did not blow a fuse making it a "leak" and not a short. I see this all the time......I cannot believe the fuse itself was the issue.