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You might try cleaning the fan and motor just for grins. The fan draws unfiltered cabin air across the thermistor temperature-sensing element, so it gets a more accurate read than it would heat-soaking in the dash. More important during the blizzard season in the Florida panhandle area than the rest of the season there. Still nice to have everything working as designed.
A little disassembly and some compressed air, followed by a couple drops of oil for the motor bushings, will often revive a "failed" fan motor.
Thanks, @dr bob . I will most definitely check into that when I have the center console out (but that may be a little while) ... The rest of this is as much a reminder for me, as it is anything else.
Using Dwayne's Guidance here, I went through the Vacuum connections and need to replace the Footwell flap Valve Actuator (which will happen once I have the console out).
Sadly, a prior owner snipped all of the hard lines in two and then patched them back together with rubber unions at the break in the rigid lines. It made for easier testing but it is still fairly stupid.
I will also be getting one of Roger's higher quality heater valves but for the time being, I have replaced the suspect heater valve with a Four Seasons Petcock (talked about here) and I have capped the Yellow Footwell Flap line at the solenoid console, rendering footwell flap inoperative.
To properly repair my AC, I will need:
1. A New Heater Valve
2. Footwell Flap Actuator
3. Either a renewed or replace Dash Temp Sensor Suction Motor
In the meantime, at an outdoor temperature of 87F at 7PM, I measured 38-40F at the center vent. This 928 has not likely been this cold inside in a while!
I also fully cleaned the condenser with Coil Cleaner from the Home Depot, which seemed to be necessary by all the dirt which came out. Hoping this helps with coolant temperature control and reducing heat soak of the radiator while running the AC full blast.
To be SURE to control some of the heat soak, I removed the Cooling Flaps Motor in front of the condenser as I am installing a relay activated fan in front of the condenser (Yes, Fans on both sides). The specific fan, which I've also used on my 1990 is
AC is truly working. Gets to sub 40F with external temps in the 80s. In the 90s it runs between 50-60f out the center vent. Might be a little low on refrigerant or it might be the best my system can do.
Its a black car in Florida, so I will take it!
The third cooling fan keeps heat soak away and the coolant temp is generally atvtge 1/2 Mark.
My exhaust decided to loosen up but that's all part of the adventure.
I guess I never saw in the thread anything indicating exactly what was blowing the fuse...?
I have the same issue. I cant figure out if something is shorting in the controller unit or exactly what the issue is. I can get a fuse to last much longer with the fan turned up only to 3. On 4, it's going to pop within maybe 5 minutes to an hour. So that tells me the fan motor is working too hard.
I replaced the blower motor. No change.
I should have cleaned the coil while i was in there....it could have enough dust in it to impede airflow....
@mkhargrove
- 34 below was the source of the issue, so I unplugged that tiny motor.
Originally Posted by jej3
It appears to be 34 (Interior Heater Sniffer and Sensor Motor) is causing the fuse to blow.
I will be replacing it but should the AC still function with this unplugged? Meaning, will the sensor just be measuring incorrectly as there is no fan suctioning air in?
This car is still relatively new to me and I want to charge it up with R134A and possibly some Red Angel but not certain if I'll get full cooling with the suction motor/fan unplugged.
Glad to know the source of the fuse blowing and now excited for the potential of A/C again.
I guess I never saw in the thread anything indicating exactly what was blowing the fuse...?
I have the same issue. I cant figure out if something is shorting in the controller unit or exactly what the issue is. I can get a fuse to last much longer with the fan turned up only to 3. On 4, it's going to pop within maybe 5 minutes to an hour. So that tells me the fan motor is working too hard.
I replaced the blower motor. No change.
I should have cleaned the coil while i was in there....it could have enough dust in it to impede airflow....
The diagnostic steps for fuse 6 blowing were listed in post 10, copied below for your reading pleasure.
Fuse 6 doesn't supply power to radiator cooling fans or to the cabin fan. It supplies ONLY the solenoid valves via connections on the setting motor, the setting motor itself, and the fan for the little temp sensor in the top face of the console near the glovebox. This applies to S4+ cars for sure, description not guaranteed to fit earlier cars. Please put the year of your car in every post. We have no way to know what car you might be working on unless you remind us every time. membership allows you to add a signature section to every post with critical info included, so you don't have to type it so often.
Originally Posted by dr bob
Make sure the temp slider is not at extreme cold or hot, and the function slider is set to the off position. Check to see then if the fuse blows. If not yet, move the slider among the available positions, watching at each position to see if the fuse pops.
If the fuse still pops right away, seconds after the key goes to on, unplug the setting motor by the driver's toes and do it again. The setting motor passes current to the vacuum solenoids, so if unplugging that saves the fuse, you have a short in the solenoids or wiring. Use your ohm meter through each solenoid coil to test for shorts to ground via the plug at the setting motor.
If the fuse still pops, unplug the center temp sensor top of the console, where fuse 6 power runs the little fan for the sensor.
I swear that seen what seemed like a light puff of smoke to the top right of the console a couple times....along with the smell of melting wires. Maybe #34 was shorting out....
05-20-2019, 02:07 PM
