Techguy Posted August 1, 2023 Share Posted August 1, 2023 blower motor went out on my 85 with ac. bought one from amazon blower it came with different connectors, so i chopped off my old ones and spliced them on the cables that came with this. i tried all combinations but could not get the fan to work. im returning the fan, but all the other sites where im looking for this part dont show the right connectors. what am i missing?> Link to comment Share on other sites More sharing options...
grumpin Posted August 1, 2023 Share Posted August 1, 2023 Is it factory A/C or dealer installed A/C? Could have came with a non A/C blower. And this is a guess on my part! Link to comment Share on other sites More sharing options...
Techguy Posted August 1, 2023 Author Share Posted August 1, 2023 Is it factory A/C or dealer installed A/C? Could have came with a non A/C blower. And this is a guess on my part! thats the odd part, its got a weird ac setup. gary had told me its a dealer installed ac. but he cab looks like factory ac. ill get pics tonight for ya Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted August 1, 2023 Share Posted August 1, 2023 Did you consider that the thermal fuse in the resistor block might be bad? It looks like a tiny little can. (Kind of what we think of a resistor) The blower has power all the time in run, and the speed control just switches different resistor coils to ground (or no resistor for high) This is the little red or yellow fiberglass panel screwed into the plastic plenum inboard of the blower motor. It can cause a fire if leaves or mouse nest get into those hot springs. I'm going to suggest that you ohm out the resistor block. Link to comment Share on other sites More sharing options...
Techguy Posted August 2, 2023 Author Share Posted August 2, 2023 Did you consider that the thermal fuse in the resistor block might be bad? It looks like a tiny little can. (Kind of what we think of a resistor) The blower has power all the time in run, and the speed control just switches different resistor coils to ground (or no resistor for high) This is the little red or yellow fiberglass panel screwed into the plastic plenum inboard of the blower motor. It can cause a fire if leaves or mouse nest get into those hot springs. https://forum.garysgaragemahal.com/file/n139003/YH25.jpg I'm going to suggest that you ohm out the resistor block. ill check that out thanks Link to comment Share on other sites More sharing options...
Techguy Posted August 2, 2023 Author Share Posted August 2, 2023 Did you consider that the thermal fuse in the resistor block might be bad? It looks like a tiny little can. (Kind of what we think of a resistor) The blower has power all the time in run, and the speed control just switches different resistor coils to ground (or no resistor for high) This is the little red or yellow fiberglass panel screwed into the plastic plenum inboard of the blower motor. It can cause a fire if leaves or mouse nest get into those hot springs. I'm going to suggest that you ohm out the resistor block. this is the connections that mine have Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted August 2, 2023 Share Posted August 2, 2023 this is the connections that mine have I'm not sure how that works with your truck. The blower motor has power in run. The ground side of the motor goes to the resistor block, and from there power out of the three coils goes to the climate speed control in the dash, which selects which resistor to ground. It's good practice to remove/inspect the resistor block on occasion to make sure there's no tinder caught up in it. If you have a MM there's not much challenge to see how the fuse feeds all the coils. Check for continuity across the fuse, and if you like you can check the resistance of each coil (but they will all seem low because you're not loading them enough to glow) Link to comment Share on other sites More sharing options...
Techguy Posted August 2, 2023 Author Share Posted August 2, 2023 I'm not sure how that works with your truck. The blower motor has power in run. The ground side of the motor goes to the resistor block, and from there power out of the three coils goes to the climate speed control in the dash, which selects which resistor to ground. It's good practice to remove/inspect the resistor block on occasion to make sure there's no tinder caught up in it. If you have a MM there's not much challenge to see how the fuse feeds all the coils. Check for continuity across the fuse, and if you like you can check the resistance of each coil (but they will all seem low because you're not loading them enough to glow) alright i check it out, and update here. ty again for the help Link to comment Share on other sites More sharing options...
Techguy Posted August 3, 2023 Author Share Posted August 3, 2023 I'm not sure how that works with your truck. The blower motor has power in run. The ground side of the motor goes to the resistor block, and from there power out of the three coils goes to the climate speed control in the dash, which selects which resistor to ground. It's good practice to remove/inspect the resistor block on occasion to make sure there's no tinder caught up in it. If you have a MM there's not much challenge to see how the fuse feeds all the coils. Check for continuity across the fuse, and if you like you can check the resistance of each coil (but they will all seem low because you're not loading them enough to glow) so i assumed the resistor was fine before because the fan would come on but the bearings were bad. that prompted to me to replace the fan, ill test the other and report back Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted August 3, 2023 Share Posted August 3, 2023 so i assumed the resistor was fine before because the fan would come on but the bearings were bad. that prompted to me to replace the fan, ill test the other and report back Ahhhh, I didn't understand from your post that the bearings were bad. Just that "the blower motor went out". Then that you cut the connector off and couldn't get the new motor to work either.... This clicked in my head that it was not the blower, but something else (and that "else" can often be the resistor fuse, because people don't even know it's there!) Link to comment Share on other sites More sharing options...
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