Fan Voltage Drop Solved!! (I think?)
07-12-2010, 11:08 PM
#1
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Thread Starter
Fan Voltage Drop Solved!! (I think?)
First, thanks to Dr. Bob, Mr. Merlin, Alan, and anyone else who provided troubleshooting tips. I think I have finally solved my voltage drop issue. I have been fighting low voltage that seemed to be temperature dependent. Voltage would be fine until ambient temps started to heat up, then the voltage would drop as indicated by the dash gauge. I verified the drop at the hot post and at the battery. In gear at idle, with A/C and headlights on voltage would drop to 11.2 to 11.5 at the hot post. I had finally narrowed it down to the blower and A/C circuit. This weekend I followed someones advice and disconnected the A/C compressor clutch and turned the A/C on to just energize the fans. Sure enough the voltage drop on the dash and via DMM at the hot post was immediate. If I unplugged the fans and the clutch and turned on the A/C, no voltage drop. Tonight I pulled out the fans, extracted the terminals from the plugs, and clean/tightened them up. While I had the fans out I popped the covers off of the terminals on the fans and found this ( I slipped the razor blade in to help make it more visible)
The blade connector in the plug is supposed to be soldered to a solid buss that enters the body of the fan. I had one broker solder joint. After a quick cleaning and a good hit with some rosin core solder I put everything back together. Now with the engine hot and in gear (brake on and wheels blocked of course) running A/C at full, rear A/C full, headlights, fog lights, and stereo I show 11.9 to 12VDC at the hot post. I still have a pretty sluggish and not very accurate dash gage (it shows less than 12V when the DMM shows 12V) but at least I can put a near full load on the system and not have the headlights dim sitting at a stop light. Glad I found it and did not burn up the fan from the poor connection.
Thanks again to all that gave advice and commiseration.
Mike
The blade connector in the plug is supposed to be soldered to a solid buss that enters the body of the fan. I had one broker solder joint. After a quick cleaning and a good hit with some rosin core solder I put everything back together. Now with the engine hot and in gear (brake on and wheels blocked of course) running A/C at full, rear A/C full, headlights, fog lights, and stereo I show 11.9 to 12VDC at the hot post. I still have a pretty sluggish and not very accurate dash gage (it shows less than 12V when the DMM shows 12V) but at least I can put a near full load on the system and not have the headlights dim sitting at a stop light. Glad I found it and did not burn up the fan from the poor connection.
Thanks again to all that gave advice and commiseration.
Mike
