I have an '84 240 with an AW70 transmission. The OD is sporadic when the weather is wet. Since I live near Portland OR, wet weather is October to April, and then some. The switch of the shifter is good, as is the relay. I had been experiencing occational fuse blowing, but traced that to a short on the transmission case. Luckily, I never fried a relay. However, I did have to re-solder some joints when I got the car. I don't know too much about this OD unit as I have only driven the car for about a year. I had an 82 with an M46 for 7yrs. I know that system much better. The solenoids sound like they are different. Anyway, some days it works fine even if wet out, and others it doesn't. If its actively raining, there's a better chance of problems. The dash light always behaves properly, and the relay trips on que. Sometimes the OD will decide to kick in half way into my comunte (30 mi), and other times it won't. Sometimes it kicks on and off quickly, every couple second or so (very annoying). Any advice/suggestions/experiences appreciated.
Thanks,
Ben

One thing to check would be moisture at the fuse panel. Mine used to get water on it because of a previous owner allowing the windshield to leak through. It came down right on top of the panel and cause corrosion at the contacts.

DanK

That's a good idea. Luckily, I don't have that problem with this car. I did on a 78 VW though. I had to kick the fusebox to get the wipers and brights to work.
Thanks for the effort.

Reconsider the relay, it may look perfect and still not work properly. I bench tested mine everytime it acted up and always worked on the bench. I bit the bullet and bought a new one, it worked fine since, go figure.

I recommend romoving the OD relay in your center counsole and resoldering all of the joints. The OD is intermitant because you probably have a bad solder joint on the OD relay.

Wynn

The relay is sound. I've tested it on numerous occations and observed it under a magnifying glass.
Thanks though.

The cracks that form on the relay printed circuit are very hard to see. I'd re-solder the relay (all connections) and try again. A relay with cracks in the solder joints can test good on the bench and not work after replacing it in the car. It might be the handling, position, or change in temperature, who knows?

I already did that. I even put in a few jumpers because a few of the traces on the board had gone bad.