Blower Relay Weird Voltage

QueueAK

QueueAK

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Joined
Oct 2, 2022
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Location
Alaska
Yet Another Blower Motor Post

To get it out of the way this is what I know and have done.
  • Switch panel has been replaced
  • Melted wires are replaced with heat shrink female blade connectors
  • Relay has been replaced
  • Resistor has been replaced
  • Blower motor works (12v wired to motor or using harness)
  • Fuse 8 and 1 both are 12v and working
  • Bench tested relay, 12v I hear click and circuit closes
  • Jumper the power bypassing the switch, blower works, speed selector works
  • Jump the 12v to the blue/white on the relay plug , blower works, speed selector works
  • Blue/white wire to the red/green on the relay plug to temp on panel is 35mv
I think at this point the thing I am trying to figure out is the low voltage to the relay switch (35mv at the blue/white wire). I have tracked (and tested continuity) the blue/white wire to a large pale green connector where it has a red/green this wire on the other side which is a short jumper to another red/green wire that leads to the temperature selector dial at the hvac panel.
1664754449728.png
 
Without a schematic being handy right now, I can only give one solid recommendation... replace the fan motor. Despite it working, it's clear its windings are starting to short together due to the shellac insulation on the windings breaking down. That causes it to start drawing excessive current which is why everything melted and burned up.
 
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None available locally unfortunately but Autozone has a 20% code now so I've got one on order. I'll try that Thursday or Friday when it gets in and see what happens.

I'm the meantime I'm open to any suggestions.
 
IMG_9938.jpg


According to the drawing in the Factory Service Manual; the Dark Blue/ White wire is terminal 2 for the Blower Relay Coil connector C205.
Check the terminal 9 wiring at C205 to see if there is a burned or dirty terminal connection
 
Last edited:
QueueAK said:
None available locally unfortunately but Autozone has a 20% code now so I've got one on order. I'll try that Thursday or Friday when it gets in and see what happens.

I'm the meantime I'm open to any suggestions.
Click to expand...
The LAST brand you want to run there is a Duralast from Autozone. If you want to buy locally at least get NAPA's top/best/premium brand they carry. Or get it from www.rockauto.com who usually has a very good selection. I would have made a recommendation or two from their list of fan motors but you never mentioned your TJ's model year and your Profile hasn't been filled out yet.
 
QueueAK said:
Yet Another Blower Motor Post

To get it out of the way this is what I know and have done.
  • Switch panel has been replaced
  • Melted wires are replaced with heat shrink female blade connectors
  • Relay has been replaced
  • Resistor has been replaced
  • Blower motor works (12v wired to motor or using harness)
  • Fuse 8 and 1 both are 12v and working
  • Bench tested relay, 12v I hear click and circuit closes
  • Jumper the power bypassing the switch, blower works, speed selector works
  • Jump the 12v to the blue/white on the relay plug , blower works, speed selector works
  • Blue/white wire to the red/green on the relay plug to temp on panel is 35mv
I think at this point the thing I am trying to figure out is the low voltage to the relay switch (35mv at the blue/white wire). I have tracked (and tested continuity) the blue/white wire to a large pale green connector where it has a red/green this wire on the other side which is a short jumper to another red/green wire that leads to the temperature selector dial at the hvac panel.
View attachment 364004
Click to expand...

So you problem is the blower does not operate unless you jump 12v to the blower relay? You have a open circuit between fuse 8 and the blower relay. Split the circuit in half check voltage at c205 if no voltage move to connector c202 I’d no voltage check for voltage coming out of the fuse box.
 
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Jerry Bransford said:
The LAST brand you want to run there is a Duralast from Autozone. If you want to buy locally at least get NAPA's top/best/premium brand they carry. Or get it from www.rockauto.com who usually has a very good selection. I would have made a recommendation or two from their list of fan motors but you never mentioned your TJ's model year and your Profile hasn't been filled out yet.
Click to expand...

I got the Four Seasons brand, it seemed to have better reviews than the Duralast. I'll give it a shot and see what happens, if no change I'll take it back.
 
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Someone on a different forum had a unlikely possibility that turned out to be the solution. The grey connector C-202 above the driver side foot area has a blade connector in that big grey connector which was shoved out for some reason. I was able to stuff it back into the plug and get a solid connection.
 
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I would like to install an extra switch for the blower motor - I think this has to be done somehow via the relay. Is there a way to switch off the blower motor in general and switch it on again when required - the control panel for the air conditioning no longer has any function and the switch for the blower is fixed. I have installed a new heating system so that the flaps can no longer be moved.
 
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