Converting to r134a? read this before doing it...

[mcm185]

Has anyone tried this successfully and does your compressor run engaged all the time? The instructions appear backwards, based on above you are replacing the Low pressure switch with a new high pressure switch and essentially by-passing the old HP switch... Shouldn't it be the other way around? I'm about to do this on my car and based on the wiring diagrams it appears that all the blk/red wires (1L, 2L) shoud be joined to 3L (which is also joined with 2H (Blk/yellow). 1H (blk/white) would be on 1 side of the new switch and 1L, 2L, 3L and 2H would all be on the other side of the new HP switch... 3H and 3L should be the same wire or spliced together on the harness... this would retain the fuction of the HP switch which will turn the compressor off when the pressure gets to high... anyone follow? I'm just trying to figure this out to do it on my car, i'm adding AC to a car that had it removed and the connectors have been cut off.

[Me+SPEED=]

BMW part # 6113 1 378 400 to replace female connector on wiring harness to match new style pressure switch.

[cory58]

Has anyone tried this successfully and does your compressor run engaged all the time? The instructions appear backwards, based on above you are replacing the Low pressure switch with a new high pressure switch and essentially by-passing the old HP switch... Shouldn't it be the other way around?

Same question. I need to convert my Touring to the single HPS. Can anyone verify from first-hand experience that the wiring instructions in the OP are correct?


Thanks, Cory

[jlevie]

BMW part # 6113 1 378 400 to replace female connector on wiring harness to match new style pressure switch.

I am not going to go back through all the old posts, but the right way to do this is to use the new hi/lo pressure switch and the adapter mentioned above.

[cory58]

I am not going to go back through all the old posts, but the right way to do this is to use the new hi/lo pressure switch and the adapter mentioned above.

Jedi Master,


Thanks for responding. My HPS was already converted to a the 134a switch, and the harness plug matches the plug on the new Santech HPS I just bought. What I need to do is figure out the wiring to eliminate the LPS, which was not done when the system was converted.


Here are the wiring instructions from the OP.


ORIGINAL SET UP
The cables that go to the high pressure switch are three:
1h. Black with white stripe
2h. Black with yellow stripe
3h. Black
2h and 3h go together at the connector

The cables that go to the low pressure switch are three:
1L. Black with Red stripe
2L. Black with Red stripe
3L. Black
1L and 2L go together at the connector

CONVERSION SET UP

• 1h, 2h, 3h are ALL soldered or crimped together
• The new high pressure switch has two cables, one connects to 1L and the other to 2L+3L (through a connector).

The rationale is that by doing this the old high pressure switched is eliminated and the new high pressure switch replaces the old low pressure switch. In this way the A/C Clutch Monitor Input and the Compressor Control remain connected to the rest of the system via the new high pressure switch.


Thanks, Cory

[Frog]

I am doing the r134 conversion on my 1984 318i. Can anyone assist on how to wire the new pressure switch?



Or should I keep the old setup low/high switch with old dryer?

[mlytle]

old thread but i am converting my e30m3 now and found this thread.

the instructions in this thread are not applicable across all e30's. note the differences in the wiring diagrams between the first post in this thread and the post above mine. the LP and HP switches are reversed in the BMW ETK diagrams. BK/RD goes to LP switch in first post. BK/RD goes to HP switch in other ETK. don't know what car the first ETK diagram was for.

the TSB shows the two separate female spade connectors as the ones to be jumped together. BK/RD and BK. on my 88 that is the LOW pressure switch. the single connector is what the TSB shows to adapt to the new switch. that is the wiring to the HIGH pressure switch.

this is opposite what OP's instructions indicate, unless i read them wrong several times... according to the TSB, the new switch should replace old HP switch, not the LP switch.

here is thread with TSB pics.

https://www.r3vlimited.com/board/forum/e30-technical-forums/general-technical/228112-a-c-pressure-switch-problem-i-think

just FYI. all e30's are not the same.

[Lugnuts]

Resurrecting this old (useful!) thread to mention that, like mlytle, the images in the BMW TIS mirror the connectors in my 10/87 325i.

The low pressure switch connectors are cut and joined together. The new all-in-one pressure switch replaces the old high pressure switch.

My old low pressure switch used 2, female black spade connectors (3 wires in total), which I cut and soldered together, as per the BMW TIS.

What I'm not sure about and would appreciate some help with is, which way round the wires are connected for the new high pressure switch.

The existing white high pressure switch connector on the engine harness has:

• 2 black wires going to 1 pin (one wire is slightly thinner)
• 1 black/white wire to the other pin

Provided this pairing is maintained with the new connector, does it matter which way round they're connected to the new switch?