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I was reading some people having issues to identify the source for heater blown fuse.
Since I faced this week the same problem and I have been able to identify it on my 74, here it goes for whoever might help to.
I first disconnected all the HVAC connector located in the engine bay (resistor, blower motor, AC pressure switch, relay, compressor) in order to narrow the source of the problem. This changed nothing, and the fuse continued to blow as soon as I turned the key on.
Once the engine bay devices were discard I focused myself on the Air conditioning control unit. Aparently everything was OK, I unplugged all the connectors (4) except the master switch...one more check.....but fuse blown again...so the only one missing was the master Switch.
Once unplugged, was quite clear that something was going on due to that melted connector. I replaced the connector with a new one but still blowing the fuse, so next step was dismounting the switch (be careful because it's like 12-14 tiny pieces puzzle which come all apart and is not easy to install back without instructions) that was when I saw that a short was happening with the metal frame due to a bad screw isolation. Turned the key on and this time the fuse survived.
I have ordered a NOS master switch which I found, becuase it seems that bubba already paid his attention on the existing one in the past and couple components were missing.
Heater blown fuse problem fixed
, so next step was dismounting the switch (be careful because it's like 12-14 tiny pieces puzzle which come all apart and is not easy to install back without instructions) that was when I saw that a short was happening with the metal frame due to a bad screw isolation. Turned the key on and this time the fuse survived.
