How many amps does an AC blower use on high?

[Northcoast300h]

...on a 1970 300 with A/C (nonATC). I think mine is pulling a max of 11amps on high, but I don't know if I'm measuring it correctly. My blower no longer works on high speed and I read the solder connections on Chrysler speed switches melt after awhile since they are only rated at max of 12amps. I'd like a normal high speed rating and what the max rating is. Thank you for your help.

 

[CBODY67]

Have you done a significant search of the wiring itself? The fan switch controls the circuit/resistor in the blower motor resistor, in the outside of the a/c case. Curious of the source of this alleged design flaw in Chrysler electrical systems?

The main issue I've seen in the '69-'73 C-body a/c systems is that they seem to not blow as hard (on High speed) as the prior '65-'68 cars do. Compounded by the additional interior volume to cool on the fuselage cars. Never did need to replace a blower motor or related switch, respectively. I sold a LOT of fan switches for Chevy Astro Vans with melted fan switches (one guy was on his third switch!).

Just some thoughts and observations,
CBODY67

 

[Sixpactogo]

The blower motor probably is dried out and dirty. Probably what caused the switch to fail on high speed. Being over 40 years old with no maintenance is a long time. Before you replace the switch and clean up the wiring connections, I would either replace the blower motor or have it serviced.

 

[Big_John]

...on a 1970 300 with A/C (nonATC). I think mine is pulling a max of 11amps on high, but I don't know if I'm measuring it correctly. My blower no longer works on high speed and I read the solder connections on Chrysler speed switches melt after awhile since they are only rated at max of 12amps. I'd like a normal high speed rating and what the max rating is. Thank you for your help.

I think 11 amps draw is about right.

Before everyone starts all over again with advice, perhaps you should reference this thread: 1970 Hurst heater/AC blower fan won't go to high, help please

Per your test on that thread, the blower sounds good, but the symptoms of not shutting off points to the vacuum switch being the issue or possibly the blower switch... or even both.

They aren't that hard to change once you pull the radio ... which is easy to do...

 

[Big_John]

Here's something to watch. Note that they are saying 15-20 amps.... Granted, that is for a new car, but I've never seen the spec for a '70. (although... I now want to open my FSM and look LOL)

 

[furious70]

I don't know amps, but I can tell you with a resealed box, new motor, and a relay with new wiring feeding power to it, I'm still unhappy with the amount of air I get.

 

[live4theking]

I don't know amps, but I can tell you with a resealed box, new motor, and a relay with new wiring feeding power to it, I'm still unhappy with the amount of air I get.

I agree that more airflow would be better. What is the problem though. Restrictive ducts? Blower capacity? How much voltage actually gets to the blower? I read somewhere that modern cars regulate the airflow be switching the blower rapidly on and off at full power to control the force of the airflow. Essentially the amount of time on is increases while the time off decreases to increase air flow. High is full on.

 

[furious70]

I know I lose some through my duct sealing. The vintage air setup on charger is far more forceful.