Overdrive Light won't come on

[maillemaker]

So I just replaced my shift bezel on my 1995 Mustang GT. Thus I replaced the OD switch.

On my original switch, I put a voltmeter on it and it was not detecting continuity when the switch was pressed. Nor was there any change in resistance.

With the new switch, I put a voltmeter on it also and there was no continuity beep when the switch was pressed. However, there was a change in resistance.

When I got it all installed and fired up the car, the OD switch worked fine. Push the button, OD OFF light came on on the dash.

However, I tested while going down the road, and it doesn't come on. I can tell the transmission is down/upshifting when you press the button though, so the button is signalling the transmission. It's just not consistently turning the light on and off on the dash.

Any ideas?

I'm about to pull the cluster again as the new LMR bezel has to have some plastic removed so that the trip odometer button is not continually pressed. I'll pull and re-seat the bulb when I do that.

 

[white95]

At face value, I'm no automatic guy, it seems like a poor connection somewhere. Did you dig into this further?

 

[maillemaker]

I'm suspecting a poor connection at the light bulb. The OD switch works fine - when you press it the transmission drops out of OD. The lightbulb sometimes comes on, sometimes does not. I have not had a chance to pull the cluster and fix the trip odometer problem yet. When I do I will pull the bulbs and clean the contacts.

 

[07GtS197]

When you turn the key to the on position (not start) does the od off light always come on or follow the same pattern?

 

[white95]

I'm suspecting a poor connection at the light bulb. The OD switch works fine - when you press it the transmission drops out of OD. The lightbulb sometimes comes on, sometimes does not. I have not had a chance to pull the cluster and fix the trip odometer problem yet. When I do I will pull the bulbs and clean the contacts.

This is the course of action I’d suggest. Tackle the easy stuff first lol

 

[maillemaker]

So tonight I pulled the instrument cluster again. I filed down the standoff for the plunger for the trip odometer (It's an LMR replacement and you have to do this to make the trip work on 94-95s). While I had it out, I pulled all the idiot bulbs and cleaned all the contacts with a pencil eraser and a cotton swab with a touch of rubbing alcohol. Put all the bulbs in.

Now my trip odometer works again, and lo and behold, so does the OD OFF light. (So do the rest of the idiot lights).

So, I'm guessing the problem was a loose bulb. I'll test it more as I drive it around this week.