Gen 1 AC Refrigerant Refill Tips

Also to add to my

Where oh where does one find a C type 50, 40 A fuse? I’m having trouble tracking this on the Internet.

 

No. Just the same as if it were a Dodge Pickup.

Sandy, you can keep the engine from going into hybrid mode (shutting off) by pushing both the a/c and the max buttons so that they are lit. Engine will stay on and at idle.

If you can go to Autozone, they have an a/c tool with a trigger mechanism and a gauge. The trigger is very good, it will keep the left over refrigerant in the can for months. BTW, Walmart has had cans this spring for $4.99, a very good price.

 

If you can't find one at a chain auto part store, try a NAPA store or the local dealership. Autozone has them, part number is BP-FMX-50-RP. If you google that descriptor, all sorts of sources will come up including Amazon. But it really is a normal Bussman fuse.

 

Thanks for this info Brian.
Farther up my post, I’ve detected my AC fans are not working. I suppose I’ll have to investigate this too. Perhaps it’s just a fuse?

 

That's an excellent question. Without those fans, the A/C will not cool well. Moreover, those fans are responsible for engine and inverter cooling also. Finding out why they're not running should bubble up to a high position on the to-do list; in addition to being implicated in your poor A/C performance, unsolved, the problem could get more expensive than that.

That's what it would mean under specified operating conditions (those are laid out precisely in the manual, where sight glass observations are covered).

You haven't got the specified operating conditions, because the condenser fans aren't running. Without those to pull air through the condenser, the refrigerant vapor passing through the condenser will not all condense to liquid, leaving you with ... bubbles. So, the fan problem must be fixed before you can take the sight glass at face value. (And fixing the fan problem may well fix your cooling problem. If it doesn't, then you can return to the sight glass for a good reading.)

This is also a serious concern. Unless you are somehow actually missing or changing a step somewhere, this indicates a real problem with your A/C control system. That also would have to be bumped up the list to fix.

But as for possibly changing a step somewhere, that really does sometimes happen, when we're trying to communicate procedures over a distance; I can't quite see what you're doing, and I've had other help sessions where it turned out the person was actually doing something slightly different from what I was saying, consistently, like six times in a row, before we figured it out. Sometimes it can help if you just ask another person (doesn't have to be anybody special, just a different pair of eyes) to read the same procedure and try to follow it, and see if something different happens. It does, more often than you'd think. I don't mean any disrespect; it happens to plenty of smart people. It would be worth trying, before reaching any conclusions about the A/C controls being bad.

You can find fuses at auto parts stores that will fit; there are similar ones in the Littelfuse and Bussman lines. If you want to have no concern about matching the exact specs (there are more specs to fuses than just the amps shown on the front), you can go for the exact fuse from the dealer.

However, it'll probably be several months before you need the supplemental heat that's supplied by that fuse, right? And in between now and then, it would be very good to find out why that fuse blew. A problem in a 50 amp circuit is not to be taken lightly.

My overall take would be that there are several problems on the list to be solved here, and if you won't be needing supplemental heat any time soon, that one can move down on the list, after the ones that are more urgent now.

The only thing that might change my take might be the chance that some of these mysteries could be related. If the A/C controller has really gone incommunicado with codes (even after somebody else tries), and the supplemental heat fuse blew ... well, hmm ... the A/C ECU is kind of low near the floor under the dash, and so are the connectors for the supplemental heat elements ... has there ever been much water or damp down in the footwells there? Does the A/C evaporator drain properly to the outside of the car?

 

Ok, I’ve checked all the AC fuses and they appear all ok. My eye cannot ascertain #36. Even the AC fan fuse is ok. My fan is black in color, not white, including the housing. It’s not turning when the AC is on. Where might I order a replacement part? I’m in an HOA community and can’t do any onsite repairs here but I could possibly order the part and take it to a local independent shop. ANY suggestions?

Re the the A/C ECU questions, no, absolutely not.
As far as I know the evaporator drains outside. My car has been in good running condition. As I say, I’ve got some cool air coming out of the vents early this morning when it wasn’t so damn hot in the car or outside.

I’ve run through the AC Diagnostic with the key in the ON and the ACC position, so I don’t think I’m missing anything.

Feeling like we are getting to the bottom of this and it’s likely the AC fan is the root cause....

 

Just hopped onto eBay to search for an AC Fan and stumbled upon this gem.... now what the heck is this and where does it go?
There’s nothing about it in my ‘02 manual.... could this be part of the problem?!

 

Well, that system isn't super complicated to troubleshoot, it's just legwork and making the right observations. There are two fans, two fuses ("RDI" and "CDS FAN", located in the driver-side underhood fusebox as already described in #26), and three relays (wait for it: "Fan no. 1 relay", "Fan no. 2 relay", "Fan no. 3 relay", in the same fusebox, right in order down one column).

The fans can run at low or high speed. They do low speed any time the A/C is on, or the engine ECU wants some cooling; they bump to high speed if the coolant temperature goes higher or the refrigerant pressure gets high. Both the engine ECU and the A/C ECU get to vote. There's an engine coolant temperature switch and a refrigerant pressure switch.

When low speed is called for, both fans are powered through the "CDS FAN" fuse, so if that one goes, there'll be no fans.

When high speed is called for, "CDS FAN" supplies one of the fans and "RDI" supplies the other. So if "CDS FAN" were blown but not RDI, there would be no low speed, and under conditions that call for high speed, only one fan would run. Or if RDI were blown but not CDS FAN, then there would be both running at low speed, but only one (the other one) for high-speed conditions.

So there are plenty of things to check ... ideally, it could turn out to be one of those things easier to replace, not the fans themselves. Those are a pain to remove, as they are wedged in with coolant hoses and refrigerant pipes all around them, and if the manual is to be believed, you can't get them out without draining the coolant and recovering the refrigerant and moving the plumbing out of the way. (Somebody might have figured out a way though, if it comes to that.)

If you like to DIY and you don't have the Repair Manual at hand, this might be the moment you reconsider that. Gen 1 was old enough to have the paper books as well as online at techinfo.toyota.com, so you've got your choice of formats. Instructions for troubleshooting these fans are on pages DI-943 to DI-947 in volume 1, and AC-65 to AC-73 in volume 2. (Those are the page numbers in my 2001 paper books; they might be a little different in a 2002 edition.)

Well, at the risk of entering broken-record territory, what you're saying it's doing is not what it does, so either something is broken or some part of the picture is missing that I can't guess at from here. If it were happening to me I'd try to get a second pair of eyes on it, or even video it and post that, so maybe somebody can spot what's amiss.

 

I’ve checked the fuses on the RDI and CDS fans and they appear normal. I’ve checked all the fuses related to anything AC related.

Now what about this AC Relay that I stumbled upon while on eBay? It says it fits my 2002 Toyota Prius and I can’t seem to find anything about relays in my 02 manual. Is there a relay diagram out there somewhere? I have no way of observing if a Relay is bad but I can certainly buy one of these if it controls the AC fan.

 

Probably not worth wasting any time on parts you stumble upon on eBay ... there are multiple relays in the car involved with HVAC or cooling. That might be one of them ... so what. Better to stay focused, diagnose the car, and if one of the relays turns out to be bad, look up (don't stumble on) the part number for the specific part needed, and go from there.

I didn't realize you had the 02 manual. Flip to page DI-944 for a simplified wiring diagram showing these fans and relays, and the subsequent pages suggest steps you can use for diagnosis. Page AC-65 has diagrams of the relays and how to test them (cooling fan relays 1 and 3 are both diagram 4, while cooling fan relay 2 is diagram 3). The following pages have on-vehicle testing ideas, followed by (ugh!) the steps for removing the fans, if it comes to that.

If my page numbers aren't the same as your 2002 edition, just flip forward or back by a few, they'll probably be close. Do you have the wiring diagram manual also?

 

I have only the 2002 Owner’s Manual as depicted here. I’m not sure what you’re seeing but mine has only 250 pages, nothing of what you describe.
No diagrams, no relays.

 

He is referring to the service manual, which you do not appear to have.

 

So I went out this evening to the Prius, to investigate once again, now that it’s not so hot. It’s only 95* in Palm Springs Ca at 10:30pm. Tomorrow it will be 113*.

Don’t hate me. The AC fan housing is black and the blades are in fact white. I turned on the AC with all AC controls on and this engaged the fan blades and both are working normally. I apparently mistook the housing for the blades because I didn’t know previously what the heck I was looking at. When I looked up some YouTube videos, I finally understood what I was to be looking for.

I also ran through the AC diagnostic check once again, per Chapman, and I can report that the AC and MAX lights simply comes on together and remain on. There is no blinking whatsoever. My AC is trying to blow cold air but it is weak.

 

I'd suggests you let someone experienced in hybrid AC system, take a look at the car.

 

Sandy, you can get a licensed digital workshop manuals on CD from Rock Auto for about $20 plus shipping. They are in the "literature" category in the listings for the 02 Prius. I have the proper paper copies for the 02, mine was an 02, but they would cost considerably more than $20 if you wanted them. RA delivered them in about 2 days.

I have the CD manuals for my 07 Highlander, they are impressive indeed!

BTW, it's kinda shocking how much effort Chap puts into his replies. If ever I meet him I'll buy him the beverage of his choice! Maybe even lunch. One of the best things about this part of the forum..

 

If you were here, I'd gauge it and see what your R134a pressure looks like. Going back a bit, does the A/C clutch click when the controls are set to automatic, coldest setting, and the motor is running? The other variable is that if the refrigerant pressure is too low, the clutch won't be engaged.

At normal engine operating temp, do either of your fans come on? I'd want to directly test them with a 12v lead to see if they are run-able. The same yards where you can get your white hood will have good fans for you to test and buy. A small motorcycle battery is very helpful, or even a UPS 12v battery for a computer backup. Again, if you were here, I'd just loan or give you a motorcycle battery. I have several. Cheaper to keep than to ship back to the supplier.

Btw, most pick/pull wrecking yards will let you take fuses and only charge nominally for relays. Used fuses are perfectly acceptable. Same deal with fasteners, I have buckets of both, Toyota plated fasteners are the best, I think.

 

Never, not even in my vocabulary. We're only going to 102 today, and 106 tomorrow and Thursday. Nice breeze tho, kinda like an all over hairdryer infront of a blast furnace. The A/C in my pickup is pretty inadequate, and non existent in the Porsche. It is one of the most important things in daily summer life in the desert south west.

 

Thanks Brian, your advice is always helpful, understandable and reassuring. Interior fans and engine AC fans are working. The AC blower and amplifier are working. I’m headed to Autozone or Walmart for the AC R134a a day this week, hoping that’s all it really needs, which was my original thought, then I inquired about a fuse which lead me down a veritable rabbit hole here for which I learned a lot and am grateful for. I always enjoy Prius Chat as a DIY’er on a dime.

Re the clutch and your “clicking” question, not certain about that aspect but it is engaging and moving.

When I get my butt into gear back into Long Beach, I have a plan to pick out several extra Prius parts I may need now that I’m aware of what I may need in the future.... I’ll be going for the hood first off. I’ve also got a slow-moving passenger door lock actuator that’s been acting up, ghosting, etc. I’ve seen some YouTube videos on how to get at that, seems doable and worth a try.

I’ll post more on the AC situation as matters develop and I can survive the desert heat.

Many thanks!

 

Don't think I'd bother with a used lock actuator, they are available on the internet for very nice prices. Both of my P's had front door crapped out actuators. Probably your chances of getting a good one are no better than 50-50.

 

Here in the Palm Springs, it’s like putting your head into a heated oven when you open the door — don’t do it!!
I don’t reside here any longer, but did for 10 years, you learn to adjust with AC, and accommodations to deal with hot cars, hot door handles, hot front door knobs, hot seats, etc.