Need some help with my 88'.

So I recently bought an 88' Ram 50 on a budget.
It runs good, but needs valve seals really bad.
I had bought it cause my daily had broke down, and now I kinda wanna fix it up.
One major problem is the overdrive not working?
The overdrive light works, and I can hear the relay clicking. But nothing?
I've been told I can ground the temp sensor?
Well that's fine..
Which one??
I found 2 by the thermostat housing. One has an orange wire, and one is yellow with a red stripe. Or am I missing one, not sure what I'm doing?

what the sensor does is once the transmission gets warm enough it tells the transmission to kick the overdrive in. keeping that in mind is your transmission going into overdrive at all? it may be more than a sensor problem it may be a linkage problem.Attachment 20290
when i first started out i had some of the same issues and with the help of these guys on the forum they pointed me in the right direction.
you might want to do a quick read on the post http://www.mightyram50.net/vbulletin...rom-the-tranny