1998 Dodge Dakota Headlight Switch Diagram

i have electrical issue in 1994 dakota. i replaced headlight switch that had a obvious heat issue across one of the metal contacts as it was dark or burnt. replacing the switch worked for a few days. now new switch is burnt on same circuit of switch. also several months prior to this ac/blower failed to work as did the controls to heater ac. anyone have a fix. thanks jeff

This is an interesting problem. I only have the electrical diagram of a 1998
Dakota to go by..but I will try to explain how both functions may be related
on yours..but you need to get a Haynes manual with the circuit diagram
for "Front exterior lighting" and "heating/a/c system (blower relay and blower)" to fully understand how your truck wiring is set up.

The fact that your headlight switch replacement has failed with the same contacts being scorched means only one thing..there is more current flowing through those contacts than there should normally be with low beam/high beam headlights operating.

Some of the reasons for this may be:

a) changing to a headlight type (HID) or Halogen where the combined
draw of both headlamps is exceeding the current carrying capacity
of the switch contacts. There is a headlamp relay in the PDC..or
at least in my 1998 wiring diagram which is used for the low beam.

b) the fusing in the PDC for the headlights may be incorrect.
Normally there should be a 40amp headlamp fuse in the PDC that is at least 25% higher rating than normal oem factory supplied headlights and combined headlight draw on high beam.

So lets say that 30 amp current is expected as "normal" with high beams on..
..and each lamp draws 10 to 15 amps of current.

The headlight switch contacts should be rated heavy enough to handle that..but if the current draw exceeds the current capacity of the headlight switch contacts,
but not sufficiently high enough to blow the 40 amp fuse..
...over time...the headlight switch contacts will overheat..and discolor.

c) The headlight switch contacts go to the multifunction stalk switch
for (high/low and flash to pass functions) then to the fog lamp relay,
and the left and right headlamp (which have their own separate grounds).

There may be some kind of condition beyond the headlight switch contacts
in the wiring that is drawing too much current through the headlight
switch contacts and overheating them.

Now..your Heater/A/C blower problem..

The A/C blower and heater controls are serviced by 2 fuses..one 10 amp
fuse in the junction block (fuse panel) provides power to the Blower Relay,
and the other 40amp fuse in the PDC provides batt to the blower motor
relay contacts.

If the blower relay coil gets energized from the "RUN" contact on the ignition switch, the blower motor receives its +12v batt from a 40 amp fuse in the PDC. The blower switch speed and function contacts are after the load side of the blower motor (-) and provide a path from ground to the A/C circuits and heater
circuits to the voltage dropping resistor block (R1/R2/R3) for the blower speeds and then to the (-)sideof the blower motor.

Now the commonality between the two functions (headlight switch and
blower circuits):

From the headlight switch there is a path to the junction block (fuse
panel next to the driver's door) and then through a separate 5 amp fuse which then goes to a joint connector (#4)
and provides illumination for the heater/a/c controls.

It may be possible that somehow the two paths have crossed somewhere..
this would explain the extra current, but without the actual 1994 wiring
diagram..I don't know where that would be.

The best thing is to get a Haynes manual for the 1994 Dakota and refer
to the electrical wiring diagrams for Exterior lights and Heater/a/c wiring
and go from there..there HAS to be an overload somewhere.

The Haynes manual will give you the fuse and splice block locations
and wire colour codes for your model year.

If I had those diagrams, I could give you more specific areas to look in the wiring on your vehicle, but not having that, I can only give you some ideas on how my 1998 is wired.

Source: https://www.dakotaforumz.com/threads/1994-headlights.1596/

Posted by: fidelmarskess.blogspot.com