'93 Wiring/Electrical Problem

[unclejohnny_69]

I have a '93 3.8 V6. The problem is that the harness that runs to the underhood light melted which caused a short and blew out the fuse. When I replaced the fuse, I noticed that some things worked and some didn't. It's on fuse #18 (15 amp).
What's working: power mirror, keyless entry, door courtesy lamps,
c-pillar lamps, and dome lamps.

What's NOT working: glove box lamp, engine lamp (obviously),
map lamp, console lamp, vanity lamps,
trunk lamp, and fog lights (switch).

I've pulled out the dash trying to find a shorted out wire and looked under the hood for the same but haven't found a thing. Are the not working items on a relay that could be shorted? I've checked the fuses in the block and under the hood and nothing's blown. I've even looked at the wires going into the fuse block and nothing looks shorted. I'm at odds end here and would appreciate any suggestions. I used to have a Haynes manual, but can't find it anymore. Would this be something that a Haynes or Chiltons would have?

P.S. Before anyone asks, I already checked the bulbs and they are NOT blown.

[97Bird]

Go to your local library and ask for the Motors wiring manual for your year. Did all of these lights work before the fuse blew? It sounds like there must be two feeds coming out of the fuse that blew since some lights work and others don't. Be sure to check all of the fuses just in case the lights that don't work are fed from a different fuse. The Motor's manual will give you this information

[unclejohnny_69]

I went to the local Ford dealership and asked someone in their service dept, and they said it sounded like a bad ground. So I went back and checked all the wires to see if they were dead or if it wasn't making a good ground. Much to my surprise they're all putting out around 12 volts. But when I plug a bulb into it, nothing happens. Then I check the wires again. Still putting out around 12 volts. I know the bulbs are good b/c I can put them in a working socket and they light up. Anyone ever hear of this or have any other suggestions?

Much Thanks!

[flewthecoupe]

If you have power at the socket and the bulb is known to be good, you're not getting a good ground somewhere you have a broken/burnt wire after the socket.

[amac209]

you need power and ground for a circuit to work. try adding an extra ground wire to the ground side of one of the sockets.

[unclejohnny_69]

Originally Posted by amac209

you need power and ground for a circuit to work. try adding an extra ground wire to the ground side of one of the sockets.

I already tried that. Didn't work. I finally wound up dropping it off at the Ford dealership and told them to look at it and give me a call with an estimate. I got a call this morning saying that it would be "time consuming"...I was thinking around half a day-ish. I asked him for a rough guess. He said he couldn't give me one...could take 2...4...maybe 17 hours. 17 HOURS!!!!! OMG! Are you out of your mind?!?! I thought that's why they were called "technicians" instead of "mechanics". I was told that they would have to go through every wire. I guess when it comes down to you just can't beat a good ol' volt meter!

P.S. any other suggestions??????


Thanks!

[97Bird]

Put a known good bulb in the socket and check the voltage on both wires coming out of the socket. If you have a 12V reading on both wires you definitely don't have a good gound conection. With a good ground connection you will have 12V on one wire and 0V on the other. My previous advice about getting a wiring diagram at the library will show the gound wires and where they are connected. If as you said you had 12V at the sockets and added a ground wire with no results then you didn't connect the wire to a good ground point. The wire must be connected to bare steel not a painted or rusty surface. Use an ohmmeter to check the continuity from the return side of the socket to a known good ground. There should be none or very little resistance between these points. Disconnect your battery before you do this so you won't damage the ohmmeter!

[ryda]

I am having a similiar problem with my 92 coupe. Turn signal worked intermittently along with rear defog, and blower panel. Now the items are not working. Their was a smell of burnt electrical wire and found the smell/smoke coming from the rear reflector night lamps. Now, the battery is being drained by the problem as well. It was explained that the relay switch could be bad, or that the voltage regulator could have some problems. I was also told to make sure that the grounding is still correct. I plan to trouble shoot the problem over the weekend and will lwt you know what I come up with in a couple of days.