The Central Hub for DSM Community and Information

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. This is where the DSM platform history is documented and archived. Log in to help us in our mission, and to remove most ads from the browsing experience.

Post a Question

Resolved 2G A/C system not working

Please Support STM Tuned

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

cswindel

cswindel

Proven Member
404
590
Jan 13, 2023
Georgia
Alright electrical nerds I need to be graced with you assistance as I am no good with electrical.

Current situation:
- A/C is not blowing cold air although the system has been charged recently without the system actually pulling in r-134 because well it dont work haha
- I dont have any prior knowledge of whether it worked or not before or after my teardown of the car
- As a side note I am running OHM harnesses throughout the engine bay and interior and running ECMLink v3

Current untested areas and possible theories:
- A/C compressor is dead and I have not ran 12v power to it such that I can test if the clutch engages or not
- Seeing if there is a setting in ECMLink that I am missing since the a/c and rad fan both kick on when signal for rad fan to kick on gets pushed out
- Thermo sensor is poop but havent checked and the wiring diagrams confuse me on where it is physically located behind the glove box and there arent really any pictures when i look.
- ACCU is poop but havent checked and not sure which wires in the connector to check but havent dug into that area yet because its a pain to reach

Steps I have taken thus far:
- Checked continuity from ECU pin 22 to A/C compressor relay in fuse box (Good continuity)
- With key in ON position and engine not running, I have voltage going to the a/c fan (connector A-39), Dual pressure switch (A-47), and the A/C compressor (A-95)
- With the engine running I checked for voltage at the same connectors and nothing concerning
- With the engine running and a/c switch active I checked voltage again and still nothing concerning. A/C compressor ground showed grounding too.
- With the engine running, I jumped/bypassed the dual pressure switch and no result came about from that
- As mentioned prior, I noticed that the a/c fan and rad fan kicked on at the same time when the signal for the rad fan got passed through the circuit (I dont know if this is normal or not but hey 2 fans is better than 1).

Just wanting to see what your inputs are with this matter before I start going down unnecessary rabbit holes without much guidance (because I will get lost, sad, and confused and it might all occur simultaneously). I believe I have covered the majority of what I have done and assessed to get this thread rolling at least
 
Solution
cswindel
A/C is working and this time it was faulty wiring entirely within the OHM harness itself (no OHM to OEM connector/pin mix ups like the last 2 issues).

Basically the white wire in the dual pressure switch as pictured:
You must be logged in to view this image or video.


Is part of their under fender connector circuit on the driver side (where the OEM one is) and, from all the testing I've done and bouncing it off the OHM "engineer", the wire from the dual pressure switch that goes into the connector as pictured (all the colorful wire one):
You must be logged in to view this image or video.


Was not pinned right such that the receiving end of that connector was not making contact. So basically the wires that were supposed to meet in this connector to form the halfway point in the circuit didnt meet up (so much...
Sort by date Sort by votes
TerminalTalon said:
I just want to note that helping digitally through a forum is more than what OHM who sold the product will ever do. Thank you @Vladimir for being on this forum with your knowledge and experience for the love of the game and figuring out issues.
Click to expand...
Absolutely without a doubt. I honestly owe a lot to the people on this forum. It's actually a big reason why I love the car so much is because of the community. And I mean it when I say @Vladimir you have been my saving grace
 
Upvote0
Im glad I can be helpful to a fellow DSMer... It's a challenge tho...this harness. There was multiple things wrong to begin with, both mechanically and electrically. I've seen a lot of techs, even some guys with a lot of experience struggle when it comes to wiring schematics and this wiring issue is 10 times worse... Not only are the wires all wrong color, they are also routed differently, not according to the diagram.

I am genuinely surprised that OHM doesn't provide a digital copy or at the very least a paper copy for their new custom wiring harness... I understand they are specialized builds but how is anybody who is not an ASE certified tech gonna figure this out.... Maybe OHM should add an option for additional $$$ they can create schematics for what they've done.

Im surprised mostly by how Cliff actually followed through with all the testing...99% of non techs would have probably just give up already. That's definitely impressive.

This forum helped me many times and everyone is always friendly and respectful....I just give back what I receive... And I do genuinely believe DSM community is the most welcoming and easy going.... I had toyotas, porches, Subaru and Nissans to compare with... Toyota guys are pretty cocky in my area and think they know it all, not sure if it's just in Illinois
 
Upvote0
Vladimir said:
Back probe with a multimeter the four pin connector at the condenser fan while it's still connected. Only the two black wire should have continuity to chassis ground. The two other wires shouldnt. Verify that....if they do it's the ground pathing through the motor windings and it will not short anything out once we jump power to energize the motor. As long as blue and orange go to pin 87, we should be safe. Worst case scenario is a blown 20 amp fuse...but I really don't think the motor is shorted out, cause you told me you've seen both fans kick on before


If that is the case you'll use a jumper wire for the relay when ,,,a,/c is ON, and it won't affect anything else in the system. You would just have to pop the hood and disconnect it, every time you park until ohm gives solution
Click to expand...
Alright so I checked the 2 black wires and they do have continuity with chassis ground whereas the blue and orange wires do not.

Can I use the power probe to just send 12v to pin 87? Do I need any ingnition or can I do it without even putting the key in
 
Upvote0
@Vladimir You're not going to believe this. I got curious due to the conditions at which both fans kicked on so I thought "maybe they share some part of this a/c fan relay". And boy do they HOWEVER, the wires don't make sense. Just like the a/c fan connector there are 2 colored wires and 2 black wires. The black wires are chassis ground, just like the a/c fan. Except, the 2 black wires have continuity with pin 87 of the same relay. So this means there are 2x chassis ground wires on the rad fan connector and 2x random color wires (the blue and orange) that all share continuity with pin 87 of the same relay. Does this add up?
 
Upvote0
Just did another test where I pulled the compressor relay and left the fan relay out too. All 4 ground wires between the 2 fan connectors all had continuity with pin 87 of the compressor relay ONLY
 
Upvote0
Pulled all the relays out this time. Found the relay where the 2 rad color wires have continuity with pin 87. Also found that all 4 ground wires between the 2 connectors have continuity on pin 87 for a separate relay. Not sure what the relay goes to but yeah
 
Upvote0
When the vehicle reaches operating temperature and commands the cooling fan to go ON, it is normal for the condenser fan to turn ON as well.

Going back to all 4 wires having continuity with pin 87. This could be a normal phenomenon for pin 87 to have ground coming from the 2 colored wires ... The circuit is not energized. Ground gets transferred from the 2 black wires that are attached to chassis through the motor windings and into PIN 87. During the continuity test the multimeter could beep or show continuity, but the resistance value is going to be very high when you test pin ,87 to chassis ground. That's why you see all 4 wires getting continuity to pin 87. Once 87 gets power and fan gets energized, 87 gets 12v with requested amount of amps flowing through it. That's what is confusing you.

Disconnect the condenser relay, put your probe to pin 87 and hit + for power for a quarter second, if the fan turns on and doesn't set the breaker in your probe, you just verified that everything is normal .
 
Upvote0
It's the pin 86 not being continues with the dual press switch and pin 85 not having a ground is what's preventing the a/c controls to turn on the condenser fan. And that also explains why the condenser fan only goes ON when ECT is higher and cooling fan gets commanded. All the circuit on the other side is doing what it's supposed to
 
Upvote0
Here. Maybe this will help you understand better. Sometimes machines have better phrasing
You must be logged in to view this image or video.
 

Attachments

You must be registered for see attachments list
Upvote0
Vladimir said:
When the vehicle reaches operating temperature and commands the cooling fan to go ON, it is normal for the condenser fan to turn ON as well.

Going back to all 4 wires having continuity with pin 87. This could be a normal phenomenon for pin 87 to have ground coming from the 2 colored wires ... The circuit is not energized. Ground gets transferred from the 2 black wires that are attached to chassis through the motor windings and into PIN 87. During the continuity test the multimeter could beep or show continuity, but the resistance value is going to be very high when you test pin ,87 to chassis ground. That's why you see all 4 wires getting continuity to pin 87. Once 87 gets power and fan gets energized, 87 gets 12v with requested amount of amps flowing through it. That's what is confusing you.

Disconnect the condenser relay, put your probe to pin 87 and hit + for power for a quarter second, if the fan turns on and doesn't set the breaker in your probe, you just verified that everything is normal .
Click to expand...
Fan came on as soon as I gave 87 power from the probe.

I guess worst case I can just set fans to always on in ECMLink but I don't want that to be a permanent fix just to have my fans wear out faster
 
Upvote0
If you want to fix it properly and not wait for OHM. Splice in/solder into your dual press switch gray wire and bring circuit to pin 86 under the relay box.

Bring any part of the chassis ground to pin 85.

Plug the relay back in and the fan will work as it should.

Or just use a jumper wire for now between 87-30 when you need a/c, just have to manually unplug it when you are not using it. Until OHM tells you how to reroute all their messed up wiring without splicing
 
Upvote0
Add Value - Be Respectful - No Trolling - No Misinformation - Participate Often!

Similar threads

  • Question
2G AC not working
Replies
4
Views
1K
GsxAwd2300
TSIdad
  • Question
2G AC Fan
Replies
1
Views
632
DSMPT
DSMPT
1greyawdtsi
  • Question
2G 2G AC Not Working - Advise Help
Replies
6
Views
1K
1990TSIAWDTALON
1990TSIAWDTALON
JGL122
  • Question
2G AC Compressor electrical issue
Replies
8
Views
3K
luv2rallye
luv2rallye
Wouter van der Velde
  • Question
1G Radiator fan and AC light not working
Replies
5
Views
2K
CrackedDSM
CrackedDSM
Boosted Fabrication
ECM Tuning
ExtremePSI
FIBA Motorsport
Fuel Injector Clinic
Innovation Products
Jacks Transmissions
JNZ Tuning
Kiggly Racing
Morrison Fabrications
Rix Racing
STM Tuned
Support Vendors who Support the DSM Community

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top