Power trim will lower but not raise

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I have a '74 mercruiser sterndrive. The trim pump works fine when I'm lowering the motor, but when I try to raise it nothing happens. The pump motor doesn't make any noise. The trim controls are sending voltage, but I do not know how to troubleshoot the system itself. I'm hoping that the trim sensor is showing that it's at full raise and keeping the pump from running. Can anyone tell me where the sensor is, hot to test it or how to bypass it? Failing that, can anyone advise how to test the pump motor itself? <br />Thanks for any help.

 

[12Footer]

Re: Power trim will lower but not raise

It is the relay on the bread board. The motor is 99% surely fine. Look for a box with relays in it. Hard to get too, but the problem is in the connector/wiring of the relay circuit, or the relay itself.<br />If y6ou can't trace it down by eye+meter, you may have to buy the shop manual.

 

[mr chapman]

Re: Power trim will lower but not raise

Please advise....