wire getting hot

[jrod92]

I have a wire that is getting hot on my 1990 gt when the car is running. just wondering what could cause this? is it just a short? what can i do to fix it? The wire is located on the passenger side in the big bundle of wiring harness. It starts out blue then is split with a 20 gauge fuse link and goes to gray with a yellow tracer and then into a connector. im pretty sure it came this way by looking at other mustangs. i could not get pictures to load but the connector is round and has 8 pins. also what does this connector go to?? thanks

 

[jrod92]

i found the the wire on this diagram its at he btottom left corner. appears to be heated o2 sensor or ignition switch im not to good at reading these things. just need help figuring out why the wire is getting so hot. should i just start by replacing the fusible link??

 

[jrichker]

Sounds like the fuse link to the O2 sensor heaters. If the O2 sensors fail or set code 41/91, this could be the reason why.

Diagram courtesy of Tmoss & Stang&2birds

Notice the wiring directly above in the diagram.




Some other good stuff to have...
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel pump, alternator, ignition & A/C wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Computer, actuator & sensor wiring
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Fuse panel layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Vacuum routing
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg



Dump the codes and see if the O2 sensors hare causing problems for the computer…Codes may be present in the computer even if the Check Engine light isn’t on.

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.
See http://www.troublecodes.net/Ford/
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is less than $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see http://www.midwayautosupply.com/p-7208-equus-digital-ford-code-reader-3145.aspx– It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.