89 Mondial t - Need AC help!

All,
I have owned a 89' Mondial t coupe for about 2 years now. Overall it has run great but the AC has never worked. The PO claimed that compressor clutch not engaging was the issue. I have since had the compressor replaced and the system has been charged and vaccumed down a few times so I don't believe its a leak (at least not a major one) and I assumed that replacing the compressor would have fixed any issue with the clutch. The last time I had the system charged about a year ago the AC worked perfectly for the rest of the day but when I took it out again a couple days later it was dead. By dead I mean no condenser fan or RPM drawdown when the button is pressed so I think the compressor is not kicking on either. I thought from these symptoms that the issue could be electrical (i.e. burnt connectors at the fusebox) but last weekend I installed a new rebuilt fusebox from Scuderia Rampante and still no AC. I wanted to install the new fusebox as a preventative measure as I had already fixed some burnt connectors but I had hoped it might help my AC too. I love my Mondial but in Houston no AC has really been limiting my drive time! Has anyone had this issue before or point me in the right direction to resolving this issue? Help!

 

My experience is with an '87 3.2, so take this with a grain of salt...

On that car the A/C electrical controls are on another pc board, which I think its located under the passenger's seat. This panel also has a relay for the A/C compressor (clutch?) and a electro valve.

There are also scattered other components that may affect the operation of the A/C, such as the cabin temperature sensor and the suction fan for it.

Also on the T's there is a switching unit on the foot rest plate (Table 149 from Ricambi's parts book)

A simple place to start would be the relay on the panel you just replaced--is it new or did you just move them over? On the 3.2 it is the same as the horn compressor so you could swap them and see if it then works.

Does the heat work normally? That would at least get the controller and suction fan off the table, assuming the T system is similar to the 3.2.

Sorry to not be of any specific help--just trying to indicate there are quite a number of places to look. I'd start with the relays then move on to the smaller A/C related board

Good luck

 

I looked a bit coser at the diagrams--the panel may be on the back of the fan box at the evaporator. See Table 151 and find items 27, 28 etc. Hardly a convenient spot but maybe you can reach in and wiggle the relays around to achieve a miracle.

 

You really need some troubleshooting skills and assuming you have some I would start with checking the system pressure, then you can hot wire the clutch without the engine running to see if it works, then test the system pressure switch and after that you can go inside to test the controls etc. A bad system pressure switch will not let the clutch turn on but you will still get the fan inside to function. That's how I would start the diagnosis.

 

Thanks for input. The heat does work normally. The relays are still the same old ones that were on there before and I have moved them around in the past to see if that was the issue. I will look into that again. I will also check for the panels you mentioned.

 

I have had very similar a/c issues.
Don't get sucked-into replacing parts until you have identified the culprit (I changed my receiver dryer at the suggestion of my specialist, but don't think that was worthwhile)
A/C is quite specialist area in my view and as Bosshogg says, need to work through logically by a process of elimination.
I used the help of a local a/c 'expert' (not one of the usual 'charge it up' merchants) - he tested pressures etc. and thought that my problem was as simple as a bad connection at the evaporator fan end of things (ie a/c wont run if the fan has no power) - not sure, but seems to be running fine now.
My advice - google yourself a real 'expert' who understands a/c systems inside and out and then work through the system until you isolate the problem

 

Good advice. I'm hoping to spend a little time this weekend trying to at least eliminate some possibilities before spending any money. I have already had the dryer replaced and the compressor. Thanks. Ill post again when I make some progress.

 

Dealing with an 88 Mondial cab - with ac compressor issues. - What I know is that the car has 10.7 Volts at the press switch, this feeds directly to the compressor. It gets this voltage from 2 sources. The AC control unit and direct from the fuse box. - Clearly I have a voltage drop situation. If I throw 12 volts at the clutch it engages and ac ice cold. Sometimes the AC works perfect. I need todo some digging.

Check your ac clutch voltage at the switch at receiver drier. I think this issue is common on these cars.

Joe

 

Here is an update on what I found so far - Checked the compressor belt looked good - fuses and relays OK as far as I can tell. With power off measured resistivity on pressure switch and could only get a very low reading. By shorting the slots in the wire plug I could get the compressor to click on and the condenser fan to come on. Still no cold air but the electrics and components seem to be functioning at least. My next step will be to try to hook up some gauges to test the pressures and I will also check the voltages as suggested earlier. I'm thinking that I either have a leak in the system or a bad pressure switch. Thanks for all the input all - I will updated again when I get some time to run more tests.

 

All - had the car in the shop last weekend - did a leak test and found that there was a leak in the system - a small leak at a connection near the condenser fan and another leak around the low side valve. Looks like when I had the new compressor put in and the system changed to R134 the tech put in a faulty valve and the refrigerant leaked out in a day. Once those were fixed the system is working great! Thanks all for the input!

 

Hello,

I have a on my compressor I was told.

Where did you get your replacement compressor.

Thanks,

Lino

 

Hi Neil,

Isn't it just the cat's meow, to be driving along with noon time temps in the 90s, yet you're cool as frosted beer just out of the fridge.

What breaks me up, is when someone selling their "baby", has this in their car's description: "just needs the A/C to be charged". Yeah, that would last about as long as your charge lasted. Then there's this one that I just thought of: "my top is down all the time ....... so who needs A/C?" That approach is all about the new owner being forced to deal with the "leaks hidden behind the trees".

Do it right, folks - fix it as you (Neil) did. Remove all the excuses. If I'm looking to buy anything, I'll skip over any ad that has that (very telling) crap included. Make it the Rock of Gibraltar!!! A qualified buyer will appreciate a qualified seller's offering - - and all will be happy with the transaction.

Sorry, I'm pontificating.

Hank

 

I have a 1988 1/2 3.2, and I'm almost certain that the AC board is located under the front passenger's toes and not under the seat. You must 1st pull back the carpet, and there are the connections, etc.

 

BTW: agree with the prior poster about the "just needs to be recharged" bull s***. Look at this rationally: if someone were selling a car for $20,000 - $35,000 and it just needed to be recharged, why in the hell wouldn't the seller do it? Let's see, to save $125.00? Baloney!

 

Hi David,

Funny, how we see this "just needs" bit in so many ads. I would put the probability (reality) of "just needs" at 5% to !0%. As such, I would put the probability of "well folks, we've go some big problems here", at 90% to 95%.

To fix a real A/C problem in a car that is decades old, a $125.00 charge would be a lottery win !!!

Ahhhhh well, - - Cheers,

Hank

 

So true .....sad but true.

Where did you get the compressor? Is there a source or replacement part?

Thank you.


Btw so right about top down and needing AC!

Scotts

 

Try these guys AC Compressor, Condenser, Evaporator and More A/C Parts at Wholesale Prices - Discount AC Parts. Give them your part number and see what they say. If there is another application, i.e. Mercedes or other, you might avoid the Ferrari tax.

 

All,
Sorry for the delayed response. Thanks for the comments - all to true - when I bought my t I got the "Just needs a new compressor". Two years later I finally found the true culprit (leaky hose) and so far its still working. I don't know the compressor source - it was replaced when the system was converted to R134 at a local shop. Unfortunately the mechanic that caused a lot of my problems with the AC leak was also the one who replaced the compressor - so the compressor I have is not correct but was made to fit. This was discovered during my last major service. It only works by modifying the belt to fit - another issue I will have to address at the next service. I have not done anything about it yet because so far its working fine. I will check my records and see if i can find the numbers/source for those.