Hello everyone!

I moved into this house around 3 years ago and this furnace was already here. We have had no problems with this furnace until now. Last night the furnace, (pre-blower) please correct me, kicked on and the burner lit good but the bottom blower motor would not turn on. The red light flashed a code of 13 (I beleive); 1 long blink and 3 short blinks. The top of the furnace was warm to the touch so I turned off the main power and let it set.
This morning I have turned the power on again and the light has reset. I turned the thermastat up to 80 so the furnace would kick on. The top blower came on and the burner lit up good but the bottom blower did not do anything. I went upstairs and the smeel of burned wires or something hot was in the house (like the night before).
I turned the power off again and took the access panals off the furnace to look at the "guts" and I turned the bottom blower motor with my finger. The fan turned freely and for a while.
I read on the inside of the panal about a jump test but I know the bottom blower motor is not working. Could you please tell me what problem is. I want to fix this myself. I am not that hip to all of the technical terms so please be descriptive and patient with me.

Thanks,
Humble

It could be the motor or the lack of voltage going to the motor. If you have a meter you can test the circuits and see where the exact problem is but since you smelled what might be burnt wiring/askril then the motor is probably bad. Test to be sure.

I taped the safety switch down and when my wife came home I had her turn the thermastat up so it would kick on. Everything went like it should but the blower motor still did not turn on. I leaned into the furnace where the burner is and sniffed to see what the smell is for sure.
The smell that came through the ducts into the house came from the burner area. The blower motor had no smell. This time the code was 3 slow blinks and 3 fast ones.

I have an older voltometer (instead of a digital readout it has a needle). Which terminals do I need to test? Where are they located?

Thanks for your patience and your post,
humbleman

I have also tried to turn the thermastat from "auto" to "fan on" and nothing happens; if this info. Helps with an answer that is great.

Thanks,
humbleman

Try this: Turn off power and remove 2 screws securing circuit board mounting shroud to blower shelf (just below induced draft blower). Locate and remove black wire from PRI-1 terminal. Locate and remove wires from HEAT and COOL terminals (note which color goes where), and connect either to PRI-1 terminal. Tape safety interlock switch and turn power on. If blower runs, replace circuit board. If not, replace blower motor.

Wow I am in awe! I di what you told me and the blower kicked right on. Is the thing on the blower frame the capacitor? It looks like a big battery.
Anyway what do I need to do next?
Thanks very much,
humbleman

Oh wait. The juice would have to go through the capacitor first. Never mind. I read the rest of your post and re- read it again. How do I know what kind of board to get. When you say circuit board you mean the brain right? This makes the 4th one on this furnace. I remember my dad having problems with the circuit board.

Since it is the circuit board. Is it possible for me to take the board out and re-soder the fitting in? Is there a special kind of soder that I should use? Is it one of the wires that I unplugged? I just thought that I would ask. If not where could I find one at?

Thanks to everyone for your patience and your time,
humbleman

Replace the board. Go to Google and do a search for the board by the furnace brand and model OR the circuit board number.

If the model # of the furnace starts with '350MAV' you will need kit # 325878-751, which is a conversion from the original. If the model # starts with '352MAV' you will need kit # 325879-751. Check furnaceparts.com or americanhvacparts.com.

Thanks for all of the information that you two are providing. I know this sounds pretty lame but where can I find the model # and is there a number on the circuit board? I haven't taken it out yet.
Thanks again to everyone for your patience and for your responses,
humbleman

Thanks. I know this sounds lame but where do I look for the #'s at? I haven't taken the board out yet. I though that I would wait until I get a new one and then go wire by wire.

Thanks to both of you for your patience, hand holding, and your time,
humbleman

OK. I have finally caught on to my mistake. I am not sure where the other 2 posts have gone. Where can I find all of the #'s at?

Anyway I want to thank you both for your patience, hand holding and your time,
Thanks again,
humbleman

Find the rating label inside the sidewall of the unit. The part number of the existing circuit board may be superseded.

Now as a follow up: We are finally in a position to get a new board. I labeled all of the wires before taking them off. I checked with the wiring diagram as I was undoing them to make sure that I did not accidentally mess them up while I was testing them. I will check in when I have put the new board in.

Thank you all for your patience and kindness.

Take your time, and good luck. If any doubts arise, come back for more advice. Remember: once the "magic smoke" has been released from a solid-state component, it can't be put back in.

Magic smoke. Be Careful. Check your wiring 2X before activation.

Ha Ha HA LOL good one HVAC1000.

I do have a question though. I have read and re-read the instructions and checked and re-checked the wiring and I still have one wire left.

It is the PR-2 wire that comes from the same place the SEC-1 and the SEC-2 wire comes from. Where does that go?

The new board I got is the 325878-751 board and this wire, from what I can see, is not mentioned.

Thank you all for your help and patience,
humbleman

Whooopppppeeeeeeee!! It works great!! It's alive... it's alive!! Ha Ha Ha Ha Ha Haaaaaaaaaa. Thanks everyone for your help I really appreciate it and could not have done it without you.
humbleman