2008 A/c Blower Motor Not working

maybe the mfd?

 

yes

 

each button stands alone. check to see if you are getting voltage at the board

 

Good luck, you’re above my pay grade now

 

You should have 12-14V on the large black wire and 0V (ground) at the white-black wire with the car in "ignition on" or "ready" modes. If you don't have power then you need to go back to the heater relay and (40A) heater fuse and test there.

You'll want to have look at a wiring diagram in the service manual.

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My diagram only shows one "HTR" relay (in the driver's side junction box).
The manual says you should pull heater fuse H (40Amps - in the engine room junction box) and check resistance - less than 1 ohm. Me, I prefer to check for power where it's supposed to be (at the battery power terminal for the heater relay).

You can use a multimeter to measure voltage level, but that won't stress a high current circuit like the heater power feed (you could have a high resistance somewhere in the circuit but not "see" it because there is no load to make voltage drop). A 12V "test light" will draw 1/4 to 1/2 amp and can determine if some power is present-(just use it only on circuits that can handle that current). For something like this heater supply, I might add some jumper wires to a halogen "sealed beam" headlight and connect one wire to the battery circuit terminal and the other jumper to ground (metal on the car body). Depending on how you wire it, some headlight bulbs will draw 5-8 Amps- which is a nice load for this circuit.

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Inspect the 40 A fuse visually, and if it does not look intact, you will need to remove and replace the whole fusible link as a unit.

 

The blower diagnostic write up in the manual doesn't mention that the 40amps fuse is part of the fusible link assembly. As mentioned you should first look at it closely. If it appears to be the same as the others next to it then it is probably ok .

Now to be clear, when you have the car in ready mode and have the blower control switched "on", then you do NOT have 12-14V at the large black wire on the 3 wire connector to the blower control module?

If that is true and the 40A fuse looks good then you need to test at the HTR relay (R2) at the driver's junction box - and/or the JB connectors to see why there is no power from the relay.

First I would use a digital meter to determine which terminals are which at the relay and what voltages are present- or not. (Only after I KNOW which terminal is the Battery feed, then I might use a headlight bulb to test that circuit if needed. There are also low current circuits in the connector that trigger the relay coil that could be damaged by a high load like the bulb)

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Sorry, but I can't read your mind. I don't know which fuse box you are referring to when you say "the other" or "that".

Near the very top of the Air Conditioning section in the service manual (pages AC-3 and AC-4) is the parts locator that shows where the driver's junction box and engine room junction box is.

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Where did you buy the parts?
Was it from Ebay used?