1985 240 m46 issue

[deezgilliams]

Just recently bought a 1985 245 w/ a m46 trans. The overdrive has not functioned since I have owned it and I finally have some free time to try and diagnose the issue. For starters I can click the button on the shifter and hear the relay/solenoid clicking (also the "5" light on the dash lights up but doesn't stay lit). It does the same thing regardless if I'm in 1st or 4th which I assume is an issue lol.
Any ideas on where to start would be appreciated

 

[Redwood Chair]

Is the solenoid plugged in?

 

[white855T]

At the very least, replace the od harness with a new one. https://www.240turbo.com/volvoharnesses.html#M46overdrive

 

[Cwazywazy]

If you can hear the solenoid clicking (ign on, engine off, in 4th) it's probably time for a rebuild or replacement.

 

[hiperfauto]

The solenoid and light get their power from the same terminal on the relay. If the light doesn't stay on I'd suspect the relay although it shouldn't click unless it's in 4th so there may be a problem with the inhibitor switch or wiring.

You can try re-flowing the solder connections on the relay and see if it comes back to life.

Here's a link to the '85 wiring greenbook.

https://web.archive.org/web/20160623101742/http://volvowiringdiagrams.com/volvo/240%20Wiring%20Diagrams/TP30808-1%201985%20240%20260%20Wiring%20Diagrams.pdf

 

[deezgilliams]

Wiring to the solenoid, 4th gear switch on the trans, and the wiring to the top of the shifter all look to be in good shape. Got a relay on the way to see if that changes anything. In the meantime I drained the fluid and removed the o.d. sump pan because it had a slight leak, refilled with type F. Now we wait and hope this brings it back to life

 

[deezgilliams]

Got the relay in this afternoon and all issues seemed to be fixed. No more "5" Light in 1st-3rd, and when I press the switch in 4th it actually goes in and stays in OD. Everything appears to work as it should.