Crazy Trim Problem - please help my sanity!

[sbbamafan]

FIrst - I will get the obvious out of the way and say I am clearly lacking in some diagnostic ability and have already wasted some money and a tremendous amount of time. I'll explain. In mid August, the day started fine. When I got back to the launch ramp to retrieve my boat on the trailer I could not raise or lower the outdrive on my 1991 Chaparral with VP 570 DP. I had someone help me get the boat out of the water and lift the drive and tie it up with a rope to put it away. So the saga began. I was hearing a clicking (the relays) both directions. I was told that generally meant that the motor was bad.

So I ordered a motor and replaced it. That did not fix the problem. I then ordered new relays and replaced them. That did not fix the problem. I then decided - screw it - and ordered a new pump with a new motor and used the new relays. I installed it tonight. Guess what - relays still clicking like that first night but no motor running.

I decided to direct wire the pump both directions and it runs perfectly - both directions. So I am stumped. Seemingly, the switches work as the relays click in both directions. My boat has two switches - one on the dash and one on the throttle. Both cause the same response. Both sets of relays get the same response - the new ones and old ones. Since the relays click, it makes me think the wiring is good. The pump motor and the pump are both new and work fine when direct wired.

The battery is good and will crank the boat and would not raise / lower the drive when direct wired otherwise. I am losing my mind. WHAT IN THE WORLD AM I MISSING HERE??? Thanks in advance!

 

[Bt Doctur]

If your hot wiring the pump motor and it runs, motor is good.
If the relays are clicking , your powering up the coils ,there working. What your missing is the main power to the relays to operate the pump . Guessing your have the small cube type relay?

 

[Bt Doctur]

 

[Scott Danforth]

the pump is an oildyne 108

do you have the square Trim display or the round trim display?

either way the trim control signals go thru the dash trim and the trim relay, prior to going to the back to the motor control relays.

the two relays get power from the dash

the motor gets its power from the fuse mounted on the B terminal of the starter

the relays are clicking because there is nothing wrong with them. they have good connection to the helm and your thumb switch.

the motor isnt doing anything because there in no 12 volt power on the big cable going to the relays

however most likely its either the fuse at the starter is bad (no power to the motor) or the connector in the cable about 12" from the motor has corrosion.

use a volt meter and troubleshoot to verify

you bought a bunch of new parts because you did not troubleshoot, you threw parts at it

so now you own a spare motor and spare relays...... now go out and troubleshoot to verify before you buy the new fuse you may need

here is a link to the manual page on boat infos site with the schematics http://boatinfo.no/lib/volvo/manuals/aq280-dpc_drive.html#/168

here is a link to the manual page with the trim system

Boatinfo - Volvo Penta AQ280, AQ290, DP-A, DP-C SternDrive Service Manual

boatinfo.no

 

[sbbamafan]

Yes - small cube relays.

For what it is worth, the trim guage has not worked for the 20 years I have owned the boat.

 

[sbbamafan]

Scott - you are right. I tend to throw parts at it for a couple of reasons. I thought I knew the problem because this happened years ago and I simply replaced the pump and all was fine. This time I thought since I heard the clicking that I would be a bit smarter and maybe a bit cheaper. Last, there is a sizeable distance and time involved - that was a total loss this time. Regardlesss, everything seems to point at a fuse near the starter. I did not know there was one. My boat is not so convenient to check. I found my old Clymer manual. I shows a fuse on a 3-wire pump but not one present on a system with a 2-wire pump. Mine has a 2-wire pump. Can anyone corroborate this? It seeems there would be a fuse either way. Furthermore, would there be an issue with changing from a fuse to a breaker for convenience if this should occur again?

 

[Wave34]

sbbamafan​

Do a test.
Unplug the motor, and attach a voltmeter to the feed wires and activate the control. If you have 12V, but the motor doesn't run when connected, and is know as good, you may have a bad ground (resistive) or bad 12V connection.
If it's the case, follow the wires to the terminals and look for corrosion.

 

[BRICH1260]

Could it be bad contacts in your thumb controlled switch on the throttle?