Air stopped blowing suddenly

[WanderingAccountant]

My air conditioning unit worked well and blew cold air, and suddenly shut off in the middle of driving. No setting works, and the fuses in the box and under the hood all appear unbroken. 
 

Any ideas?

[Minuit]

Pop the hood and give the blower motor (on the extreme passenger side of the firewall) a good smack and see if the air starts blowing again. If so, it's time for a new blower motor.

 

Got a multimeter?

[ghetdjc320]

Is the air just not coming out of the vents? Try the blower motor as Minuit suggests but if it’s good you probably lost the vacuum connection from the engine to the hvac control panel. The engine vacuum come through the firewall right behind the expansion valve. Trace that vacuum hose and make sure it’s getting vacuum since it activates all of the motors that move the vent doors and gates

[Minuit]

1 hour ago, ghetdjc320 said:

Is the air just not coming out of the vents? Try the blower motor as Minuit suggests but if it’s good you probably lost the vacuum connection from the engine to the hvac control panel. The engine vacuum come through the firewall right behind the expansion valve. Trace that vacuum hose and make sure it’s getting vacuum since it activates all of the motors that move the vent doors and gates

I assumed that the OP meant "no air is coming out from anywhere and I can't hear the fan" - but yeah, if you hear the whooshing of the fan and can feel the air coming out of the top of the dash, do this instead.

 

One more thing to check if the fan isn't working, make sure the fan speed switch hasn't melted at the connector. It's plugged into the back of the HVAC panel in the dash. If it melts or shows signs of heat damage, that means the fan is drawing too much current and needs to be replaced anyway. A member on this forum can supply the connector you'll need.

[WanderingAccountant]

Okay guys, thanks for the feedback! I changed the blower motor and the relay and seem to have solved the problem! Found a vacuum hose that was not connected, however. Anyone know where this goes?

[jdog]

it's a vent hose I believe

[silvertwinkiehobo]

I'll have to look at Maveric's but I'm sure it's vacuum.

[Pete M]

I do believe it's the vent for the vacuum lines for the front axle   

[WanderingAccountant]

16 hours ago, Pete M said:

I do believe it's the vent for the vacuum lines for the front axle   

Am I reading this correct that it should be left the way it is? I could not locate a place to plug in.

Thanks everyone for the feedback!

[Pete M]

it is how it should be  

[Pete M]

well, technically the CAD should be bypassed and all that harness should be removed and the starting point should be capped off. 

 

that is how is should be.  

[WanderingAccountant]

Okay friends, air has functioned properly for the day, and all of a sudden quit working just as before. Brand new blower motor and brand new relay. Checked fuses and both are intact. There must be a short or something wrong with the electrical. What now??

[jdog]

On 8/18/2020 at 6:13 PM, Minuit said:

One more thing to check if the fan isn't working, make sure the fan speed switch hasn't melted at the connector. It's plugged into the back of the HVAC panel in the dash. If it melts or shows signs of heat damage, that means the fan is drawing too much current and needs to be replaced anyway. A member on this forum can supply the connector you'll need.

Have you checked?

[ghetdjc320]

Also, do you have the little rubber vent hose connected to the motor? 

[cruiser54]

On 8/22/2020 at 11:25 AM, Pete M said:

well, technically the CAD should be bypassed and all that harness should be removed and the starting point should be capped off. 

 

that is how is should be.  

AGREED

[cruiser54]

Here's something to do:

http://cruiser54.com/?p=211

[WanderingAccountant]

18 hours ago, jdog said:

Have you checked?

 

17 hours ago, ghetdjc320 said:

Also, do you have the little rubber vent hose connected to the motor? 

 

I plan to check these this weekend, thank you both!

[WanderingAccountant]

4 hours ago, cruiser54 said:

Here's something to do:

http://cruiser54.com/?p=211

 

I started to work through your tip #1 to refresh the grounds and saw this!  I am looking to make this adjustment this weekend; do you have advice on the wire gauge eyelet to get?  This is the item I was going to order: https://www.mcmaster.com/electrical-connectors/ring-terminals/insulated-high-temperature-ring-terminals/

 

Additionally, I lost the grounding screw on the driver front end inner that you refer to in tip #1 and borrowed one from another location to fill the void.  Do you happen to know the screw size?  I was going to guess and order an M6 x 1 mm Thread, 20 mm Long but wanted to make sure.  THANK YOU in advance :)

[cruiser54]

#12 wire will be fine. Just harvest another screw from the inner fender and match it up.

[WanderingAccountant]

Just checking in with everyone: Some random tinkering under the hood and my blower motor started working again.  I assumed we had a loose electrical connection.  Fan speed switch is functional, and hose is connected to the top of the engine.  Added the additional ground for the blower motor per crusier54's direction.  I assumed all was well.

 

Blower motor cut off while driving and no amount of jiggling the connection will make it respond.  Any new ideas?  Fuses are unbroken.  It appears to be a bad electrical somewhere...

[eaglescout526]

Have you checked the resistor and its condition?

[WanderingAccountant]

Just now, eaglescout526 said:

Have you checked the resistor and its condition?

 

I replaced the resistor when I replaced the blower motor.  Everything seems to be good down there.

[eaglescout526]

Hmmm, worth a shot. I recently found mine to be corroded enough to not have the motor spin on level 1.

[Ωhm]

At the AC Mode Select Switch disconnect C236. Make sure you have B+ on pin C236_D. If yes, jumper C236_D to C236_E. See if Blower Motor works.

 

[WanderingAccountant]

1 hour ago, Ωhm said:

At the AC Mode Select Switch disconnect C236. Make sure you have B+ on pin C236_D. If yes, jumper C236_D to C236_E. See if Blower Motor works.

 

I can try this tomorrow, can you elaborate on what to do exactly?  I am very new to electrical issues in vehicles and am having trouble with some of your terms.

 

Thank you in advance!