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dhammika ****
Age: 49 Zodiac: Joined: 16 May 2015 Posts: 408 Location: Sri Lanka
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Posted: Mon Feb 06, 2017 15:16 Post subject: AC Blower not working |
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Hello everyone,
Yesterday I went to local body shop and done some minor rust repairs and after that my AC blower was not working. Compressor and compressor motor are working.
I can make sure that there were no wires damaged due to the repair. Only wiring related thing was guy removed the plastic clip (which attach wiring harness to the body) of the wiring harness going along driver side flow to the back and place it away from the welding area.
It was gas (oxy acetylene) welding done.
I have checked the wiring diagram and according to that, when the ignition is on, blower relay is energized and 12v should come to the fan socket and ground connection is supplied via the switch and resistor block.
+12v is not present in the blower socket, so I checked the relay located in the junction box. Relay was getting the 12v and it get energized with ignition on.
According to the wiring diagram, from relay to the blower motor is a direct connection (only goes wire junction box socket), so I'm now stuck because there is no way suddenly a break in a wire going inside a dashboard can happen.
I also noticed that wiring diagram is not actually 100% matching with the wiring I'm having.
1. Wiring diagram shows 4 speed settings L, ML, MH, H, but I'm having only 3 L, M, H
2. Colors of the wires are not matching
3. I find two resistor blocks in my AC, one mounted to the blower assembly and one to the evaporator assembly, but diagram shows only 1
So, can anybody please let me know what I'm missing or where I should look?
Thanks |
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Posted: Mon Feb 06, 2017 15:16 Post subject: Google Ads keep the POCUK free to join! |
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peteinchad LifeTime Member
Joined: 07 Jan 2013 Posts: 15079 Location: UK
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Posted: Mon Feb 06, 2017 16:53 Post subject: |
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If it happened after the wiring was unclipped and moved then it seems either a wire has broken or a connector has detached.
Can you run a new temporary wire from the relay to the blower to see if it cures the problem? You could just pass it through an open window for the test to save threading it through the dashboard. |
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dhammika ****
Age: 49 Zodiac: Joined: 16 May 2015 Posts: 408 Location: Sri Lanka
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Posted: Mon Feb 06, 2017 19:32 Post subject: |
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peteinchad wrote: |
If it happened after the wiring was unclipped and moved then it seems either a wire has broken or a connector has detached.
Can you run a new temporary wire from the relay to the blower to see if it cures the problem? You could just pass it through an open window for the test to save threading it through the dashboard. |
Thanks Pete,
Actually the wire moved is completely unrelated, it was the wire going to the driver side door switch and other components and it was moved few inches without pulling it.
Yes I can run a wire, but since wiring diagram is not matching, I'm not confident to fiddle with wiring. But anyway I will give a try. |
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peteinchad LifeTime Member
Joined: 07 Jan 2013 Posts: 15079 Location: UK
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Posted: Mon Feb 06, 2017 19:47 Post subject: |
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The wiring diagrams I have don't match my truck either
I have not looked - but is the blower wired with the silly negative wire switching? |
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dhammika ****
Age: 49 Zodiac: Joined: 16 May 2015 Posts: 408 Location: Sri Lanka
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Posted: Mon Feb 06, 2017 20:05 Post subject: |
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peteinchad wrote: |
The wiring diagrams I have don't match my truck either
I have not looked - but is the blower wired with the silly negative wire switching? |
As per wiring diagram, yes it is negative switchinh.Relay is there to aupply power to the blower when ign is on. And the current is going through the hi/med/low switch.To the ground, which is kind of silly |
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peteinchad LifeTime Member
Joined: 07 Jan 2013 Posts: 15079 Location: UK
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Posted: Mon Feb 06, 2017 20:08 Post subject: |
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dhammika wrote: |
which is kind of silly |
I wouldn't mind if it was all negative switching - but some circuits are switched on the positive.
Is this the same diagram as the one you have?
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dhammika ****
Age: 49 Zodiac: Joined: 16 May 2015 Posts: 408 Location: Sri Lanka
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Posted: Tue Feb 07, 2017 7:23 Post subject: |
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I mean drawing current through the switches without using a relay is kind of silly.
Anyway wiring diagram is somewhat similar, but not the one I'm refering
What I'm referring is page 300 (4A 204) of following manual
https://drive.google.com/open?id=0BzJBT050_Ju3UUhGRmNCaE1wd0k
on a separate note PDF Bookmarks were translated from Russian to English using google, so will see some odd bookmarks like Beep for the Horn |
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peteinchad LifeTime Member
Joined: 07 Jan 2013 Posts: 15079 Location: UK
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Posted: Tue Feb 07, 2017 8:00 Post subject: |
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It's difficult not having a manual that matches the truck.
I also have that manual in your link above but it rarely matches the wiring in my truck.
The best manual I have found is THIS ONE - you are welcome to download it if it is any use.
Once the zip file is extracted then double-click the .exe file and it gives you a menu. |
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dhammika ****
Age: 49 Zodiac: Joined: 16 May 2015 Posts: 408 Location: Sri Lanka
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Posted: Tue Feb 07, 2017 9:43 Post subject: |
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Thanks Pete, It is the same manual I got and it was pretty useful in everywhere except for the A/C wiring. |
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peteinchad LifeTime Member
Joined: 07 Jan 2013 Posts: 15079 Location: UK
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Posted: Tue Feb 07, 2017 9:57 Post subject: |
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Looking at the diagram above, if you have power from the relay then I would concentrate on the earth switching on the black wire.
The Left multiswitch must be the blower fan speed control - which switches different stages of the resistor to control the curent to the blower.
Black wiring tends to be earth wiring so it might be worth directly connecting terminal (2) from the blower to earth. If the blower works(with ignition on) then it has to be the switch or the resistor.
I know that the resistor in other makes of cars can be a bit unreliable (hence the problem Vauxhall has with their Zafiras bursting into flames) |
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dhammika ****
Age: 49 Zodiac: Joined: 16 May 2015 Posts: 408 Location: Sri Lanka
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Posted: Tue Feb 07, 2017 11:33 Post subject: |
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The relay is located in the junction box underneath driver side dashboard and I don't know what is the reason Mitsubish put the junction box in such inaccessible location.
After big struggle I was able to remove the relay and check the connections to the relay (using a male side of spade connector attached to a wire and inserting to the relay socket one by one) and all were fine. Then I checked the relay separately and it is energizing and turning on/off fine. But no 12v available at the blower motor socket. other pin of the socket is connected to the ground. (It should be directly connected to the ground when switch at the HI position bypassing the resistor block)
So I guess that there is some sort of disconnection in the wire between relay output and the motor socket. Still cannot figure out how that can happen within one hours time when only wiring related activity was moving an unrelated wire few inches.
I'm extremely reluctant to connect the relay output to the socket using another wire without finding whats going on (I'm a bit of an OCD case) |
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peteinchad LifeTime Member
Joined: 07 Jan 2013 Posts: 15079 Location: UK
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Posted: Tue Feb 07, 2017 12:38 Post subject: |
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So there is no power going through the Blue wire (on my diagram above) from the relay to the blower?
Have you removed the relay and disconnected the blower socket and then tested the wire for continuity from the relay socket to the blower socket? |
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peteinchad LifeTime Member
Joined: 07 Jan 2013 Posts: 15079 Location: UK
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Posted: Tue Feb 07, 2017 12:43 Post subject: |
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dhammika wrote: |
The relay is located in the junction box underneath driver side dashboard and I don't know what is the reason Mitsubish put the junction box in such inaccessible location. |
Because they can I removed all the rear trim panels over the wheel arches so that I could spray Dinitrol in there - and found several control boxes. You would never know that they were there if you needed to find or replace them!
dhammika wrote: |
Still cannot figure out how that can happen within one hours time when only wiring related activity was moving an unrelated wire few inches.
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Strange things happen - like my heater blowing cold air when turning left (but only occasionally!!) |
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dhammika ****
Age: 49 Zodiac: Joined: 16 May 2015 Posts: 408 Location: Sri Lanka
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Posted: Tue Feb 07, 2017 12:53 Post subject: |
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peteinchad wrote: |
So there is no power going through the Blue wire (on my diagram above) from the relay to the blower?
Have you removed the relay and disconnected the blower socket and then tested the wire for continuity from the relay socket to the blower socket? |
Yes no power to the blue wire (according to the wiring diagram it is blue, but I have blue-white wire connected to the socket)
Yes I removed the relay and removed the socket and checked continuity, and there is no continuity.
relay output is connected to the blower socket through socket C116, which is located back of the junction box, and unless you are a gecko you will not be able to access without removing the whole f****** thing. I'm really getting frustrated with inaccessibility of relays, control units, fuses now |
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peteinchad LifeTime Member
Joined: 07 Jan 2013 Posts: 15079 Location: UK
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Posted: Tue Feb 07, 2017 13:26 Post subject: |
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Sounds like the wire is broken between the relay and the blower.
This won't do your OCD much good but I would temporarily put a new wire connected to the old one as close to the ends as possible. And to make your OCD worse I would connect it with a couple of ScotchLoks so it can be easily removed if it doesn't solve the problem.
If it does solve the problem then just replace the wire with a new one soldered at each end. |
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