Yup, manual HVAC doesn't have an ambient sensor. Automatic Climate Control needs to know what ambient temp is to figure out if you want heat or AC. Beats me why they couldn't use data from just one sensor.

 

Ok so I don't have the mysteriously ground relay under the driver side dash. I'm going to buy a DVO today. Please educate me on taking the readings. I ordered a set of new headlights and want to get those put on this week if I can get this grounding issues resolved.

 

Post a link to the DVOM you have so I know what you're working with.

 

This is all I could afford

INNO 3310
http://www.equus.com/Content/Support/Manual/3310.pdf

 

That'll work just fine. Select the 200 ohm scale. Connect the probes just like they are on the first page of the manual.

Remove both low beam bulbs and check resistance on the terminals for the yellow wire from left socket to right socket. Must be less than 5 ohms. Post your results.

 

Ok so do I plug the black DVO into the yellow side of the bulb wire?

 

Both low beam sockets have a yellow wire. It is the ground wire, but it does NOT go directly to chassis ground. This is the wire we need to check from the left socket to the right socket. The probes need to touch the terminals in the sockets that the bulb normally touches when you plug it in. We know the right side is good, the problem is with the left side. Either a bad socket or a broken wire somewhere. The left socket also has a yellow with black trace wire, we're not concerned with this one....yet, so don't probe it.

EDIT: Black DVOM probe goes to one socket, (doesn't matter which socket) red probe goes to the other socket.

 

So let me under correctly, I am taking both the red and black and attaching them to the solid yellow wire on the driver side low beam connector?

 

Basically the yellow wire is routed in the vehicle like a "Y". We need to test the resistance between the two tops of the "Y". In other words, from end to end, left socket to right socket.

 

Ok thanks with the vehicle off and lights off I got a reading of 1.2