• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

heat ac switch wiring charred

ak95xj

NAXJA Forum User
Location
United States
95 xj 4.0 203,000 miles So my ac stopped working and heat stopped working suddenly(blower motor stopped blowing)..I took the cover off the hvac controls and see that the female connector that plugs into the fan speed switch was all melted and charred...

I was just wondering whats the best way to fix this

And why did this happen ..I dont want my xj to burn down
 
Why did it happen? ALL of the XJs suffer from over-engineered electrical circuits. Not the "good" over-engineering, where things are built to survive a nuclear attack, but the cheap-A** over-engineering where things are built to the absolute MINIMUMS to keep it running until it is out of warranty.

Here is a good fix: http://www.naxja.org/forum/showthread.php?t=1002774

Other problem circuits on the XJ: the headlamp circuit; the ignition switch; the charging circuit. All way "over-engineered".

One thing you can do to reduce damage to the ignition switch is to turn off ALL accessories before turning off the engine. That way on restart there isn't a heavy load shock to the ignition switch.
 
Things that make the wiring and plugs melt down:
1. blower motor getting old and drawing more current
2. connectors getting a little corroded (increasing resistance)
3. feeding lower voltage to the blower motor (the lower the voltage, the more amps the motor draws). You will notice that wiring and connectors are rated to carry a certain level of amps. That is why 6V cars had heavier wiring. At start up, the starter is drawing the most juice, reducing voltage available and forcing the blower motor to draw more amps. Like joe said - turn the fan off until after your XJ is started and generating good voltage.
 
yeah ill probably start doing that now..I haven't been turning the ac off when I park it

I crimped some new connectors onto the wires tonight and now it works again

Im looking into adding relays to the wiring like in that article above..Can I use the kind that the fuel pump etc use in our xj's? Cuz Im goin to the junkyard tommorow anyways and figured I can grab a bunch from there..These are the relays he used in the article
http://www.summitracing.com/parts/VIA-80237
 
You can find 30A relays all over any salvage yard. Most part stores will have the plastic connectors pre-wired for cheap, so if you don't want to hack up wiring harnesses at the salvage yard that is another option for them.
 
Back
Top