1990 325iC air condition accumulator drier

ryanesto · 08-03-2011, 05:41 PM

hi and HELP,
i have 1990 325 iC. upgrading a/c and having issues with the accumulator drier. the car still has original accumulator that has 2 ports for high and low pressure switches. this accumulator no longer made and the recommended accumulator has only one port for a "combined high low switch. does anyone have diagram, photo, instructions for the "retrofit" wiring. a link to instructions would be killer or a good set of photos showing how the switch is wired from the accumulator to the compressor. thanks in advance for the assistance.
ryan

coolbear1 · 08-03-2011, 08:50 PM

The pressure switches should be one that opens on a rise of pressure, and one that opens on a fall of pressure, I think the device you are replacing is a reciever drier as opposed to an accumulator. It should be mounted recessed forward of the right front tire behind the head light.
If this discribes the tank you are replacing, it is a high side device and is not an accumulator.
An acumulator would not need or have a dual pressure, or two pressure controls.
A reciever drier on the other hand has two controls, or a combination control that will interupt the compressor in the event of excessive head pressure (loss of air flow across the condenser, from a broken belt for example), or low pressure as a result of loss of refrigerant charge.
Either way they are open on failure switches.
How many connectors does the combination switch have?
Also, the switches on the old tank may tread out and you may be able to connect them to the new tank, but if I remamber correctly there is only one place to connect a switch on the replacement tank.

ryanesto · 08-05-2011, 06:59 PM

coolbear,
you are exactly correct. the old receiver/drier that is in the car now has 2 pressure switches. on for high and one for low pressures. all the new driers have only on place to attach a switch. bmw makes a modified wiring harness to use in this situation but i do not know how to hook it up, what wires to tie together to make this work. any directions or photos of an 1990 retrofit kit would be tremendously helpful.
thanks for your help and interest.
ryan

coolbear1 · 01:32 PM

Ok,
There are a couple of aproaches you can take. The control connections on the old reciever should be nothing more than a 1/4 inch male flare. If the new tank has the same fitting, but only one, you can purchase a 1/4 inch tee fitting from any a/c or appliance parts distributorfor minimal cost. It has a 1/4 inch flare nut and two 1/4 inch male fittings for you existing controls to screw onto, thus no wiring change needed. It may come with schrader valves on one or more of the male connections, you don't need the schrader valve cores, because if the control does not have a built in depressor no pressure will get to the control, just remove the valve core. screw them out with a valve core remover. (the same tool and procedure as removing the valve core on a tire).
The other aproach is electric and I don't have enough info to go there. I is not difficult, but I need to know about the specifics of the new control,its connector, how many pins and which pins do what in relation to pressure.

Just a thought;
I hope you have access to a good vacuum pump, you have to evacuate the system of air and moisture or you are waisting your time and money.

If the fittings are not as I discribe, or you can't find the adapter tee, let me know.

Good luck with it.

ryanesto · 08-07-2011, 06:48 PM

coolbear,
thanks again for your reply. the idea of a tee fitting just might work but i want to give the single switch approach a shot first. i located a guy here in nashville with a similar car to mine and i will take a look at his reciever drier set up. hopefully this will answer all my questions and i'll complete this project.
concerning vacuum: i have all the equipment and have used before so i'm good with pump, manifold guages, etc.
you've been a great help and have offered some really good suggestion; i appreciate the assiacance.
regards,
ryan

coolbear1 · 08-08-2011, 08:02 PM

I have no doubt you will make it work.

ryanesto · 08-09-2011, 06:46 PM

hi everyone,
i'm still hoping someone can post a pic of their reciever drier from a 1990 325i. i need good photos of the receiver drier and how the wiring harness is attached. my current set up has 2 switches on the reciever drier and the new configuration is just on hi/low switch. if you can help, please do. i appreciate the comments and suggestions i have already received.
ryan

coolbear1 · 08-10-2011, 12:47 PM

Ryan,
My 93 has the single pressure control set up you discribe, I can send you a picture if you like, but it will be of the top of the tank with a pressure switch with a plug with wires coming out of it. I am not sure how it would help you.
You have two plugs, with two wires each. I have one plug with three wires. your two plugs will not plug into my switch. you are going to have to first get the correct plug for the switch, and then cut off your plugs, determine what wires are common, connect both to the common on the new plug, determine what wire is the fail high control wire and connect it to the coresponding terminal wire on the new control and the same for fail low.

coolbear1 · 08-10-2011, 08:18 PM

I did a search on google and found alot of the new style pressure switches made by Bher that have two plugs.
Did you get a new style switch already?

coolbear1 · 08-11-2011, 09:30 AM

I found this set of insructions at one our hosts competitors website.....

Have the system discharged as noted above.
2. Unplug the wiring connectors for the high-pressure (longer green body with pigtails) and low-pressure
(shorter body with male spade terminals) switches which are mounted to the fitting block on the top of
the dryer bottle. Disconnect the refrigerant lines. Remove the dryer mounting bolts and remove the dryer
from the vehicle.
3. Cut the supplied connector off of the new high-pressure switch. Strip about 1/4 inch of insulation from
the cut wire ends and crimp on the supplied female spade terminals.
4. Cut the female spade terminals off of the wires which went to the original low-pressure switch. Strip
about 1/4 inch of insulation from the cut wire ends and crimp the in-line splice connector between the
two wires (the low-pressure switch is no longer used).
5. Remove the plugs and end caps from the fitting block on the new dryer bottle. Locate the Schrader valve
(looks like a tire inflation valve) on the fitting block. Of the three O-Rings included in the kit, locate the
larger one. Slip this O-Ring over the valve and seat it in the machined groove. Screw the new high-pressure
switch onto the valve and over the O-Ring until it seats, then tighten it down (the switch may be initially
difficult to thread on. This is normal, just give it a little additional torque and it will thread right on).
6. Install the new dryer bottle. Connect the refrigerant lines using the two remaining supplied O-Rings. Plug
the female spade terminals from the high-pressure switch into the terminals in the wiring harness plug
(polarity does not matter).
7. Have the system appropriately evacuated and recharged following the applicable procedures for the
refrigerant being used.
IMPORTANT NOTE: If changing from R-12 to R-134 refrigerant, the old lubricating oil must be fully evacuated from the system
before adding the new PAG oil and R-134 refrigerant.
SAFETY WARNING: It is illegal to discharge A/C refrigerant to the atmosphere. The A/C system must be discharged by a licensed
A/C technician before performing any work on the system. Failure to do so is illegal and may result in personal injury or damage
to the system.
NOTE: These instructions are to be used when updating a 3 Series 84 thru 89 to the later 90 thru 91 style A/C Receiver/Dryer. The
new pressure switch, # 64 53 8 390 971, is required when installing this updated receiver/dryer.
A/C Receiver/Dryer Installation Instructions
Call

ryanesto · 08-11-2011, 10:34 AM

coolbear,
thanks for your continued interest and help. i have ordered the switch 64 53 8 390 971 from pelican. the instructions you sent are great. along with the pics i now have of a 1990 bmw, i should be able to give this a go. again thanks and send anything else you may find. i update after the weekend.
thanks,
ryan

coolbear1 · 08-11-2011, 02:27 PM

I did some checking, the new switch acts as a low and high pressure control. it breaks the contacts low and high thus onlt two wires needed. no need for the low pressure hook up, but the two wires do need to be connected togther to complete the circuit.

coolbear1 · 08-16-2011, 09:51 PM

Have you had any progress? Your post may help countless hot people. Please let us all know how you did. Good or bad.
The real value of this forum is when sincere people help each other work through problems, no matter the outcome.
Many others may gain from the an accurate acounting of it.

ryanesto · 08-20-2011, 01:20 PM

coolbear,
just completed the ac project. purchased drier and combined hi/low pressure switch from pelican. ran vacuum for 45 min., added 2 lbs of 134a and all is well. the system cools as new!. thanks a ton for your interest and help.
regards,
ryan

coolbear1 · 08-21-2011, 05:06 PM

Good deal! You are welcome, glad to help. I am sure this post will be around for a while. Check it in a few months, you may be surprised at how many people will reference it.