Blower fan/ac not getting power

[Jonny]

Hey guys
Well..
after my alternator swap I experienced two random problems. my brake lights were staying on (plastic tab on the brake sensor/pedal cracked) and my blower wont turn on. I have gone through 4crawler's troubleshooting info and replaced the resisto pack and also checked & replaced the relays under the passenger foot well area. They click when i turn on the blower from the dash controls...but nothing happens. I used my test light and the blue plug on the blower motor is not receiving any power and when i actually push the AC button, it doesn't engage the AC compressor and the green light does not illuminate. When I turn on my parking lights the dash lights illuminate as they should and the AC button light even illuminates. AT this point I am stumped.
Possible a bad blower motor? I am assuming it would wear out gradually rather than cut out completely. could be wrong though. bad switch? if it were a bad switch, wouldn't the relays not click?
Any ideas/tips/insight would be greatly appreciated!

FWIW:
1990 4runner 3.0 5spd- GM cs130 alternator with the original alternator-to- battery/80a relay snipped and tucked away. Ran a new fused 4ga cable from my alternator to my battery. The 80a factory fuse is still in place under the fuse box, but not connected to the alternator.
hellllllllp! :ybrick: :biggrin2:

 

[Jonny]

found this:
Not getting any power to blower motor - YotaTech Forums

****I figured it out... turns out some guy wired his truck wrong when he got a high amp alternator installed. he went directly from the alternator post to the battery instead of going into the fuse box under the hood which in turn gives power to heating and air system. Still cant figure out why the cruise doesnt work though. o well the heater is boiling hot and the A/C is 40 degrees ****(from thread listed)

So..
When I snipped the original alternator wire (which according to this guy also provides power for the ac and blower) that's where I killed the blower/ac power?
I ran a new 4ga fused line from my alternator to my battery.
Any ideas on what I should do to the original (snipped) wire?
maybe upgrade the factory Alt fuse to 100 amp (105 amp alternator) and re connect the factory alternator cable?

 

[KidVermicious]

So the alternator and the blower motor share a fuse? How weird. Sounds like what you need to do is isolate the wire providing power to that fuse in the fuse box and get 12v on it.

Try PMing RAD4Runner here or on Yotatech? He's a wizard with the wiring diagrams.

 

[Jonny]

So the alternator and the blower motor share a fuse? How weird. Sounds like what you need to do is isolate the wire providing power to that fuse in the fuse box and get 12v on it.

Try PMing RAD4Runner here or on Yotatech? He's a wizard with the wiring diagrams.

Finally a reply :fro:haha
Very weird indeed. I did notice that the "factory" alternator pig tail (attached to the post on the rear side of the 60 amp alternator) is actually two wires. I winder if one runs to the 80a factory relay then in turn the battery...and the other runs to the fuse panel that supplies power to the ac system? Wonder if I hook one of them to the alternator post to draw power from? and hope that it is the right one for the ac ...and keep my 4ga fused power wire from my alt - battery. I did however pick up a 120a bussman fusible link to replace the 80a factory fuse. Going to try that route and fingers crossed everything works and the charging system still works :crybaby::ballchain:
thanks for tuning in KV

 

[RAD4Runner]

Thank for the confidence, KidV

Hi Johnny,
No bother at all. Sorry, just so busy at the office and preparing for a move. Don't have experience with the 1990 but will read/try to respond this weekend.

Does anyone have schematic for the AC system on this particular truck he can share?
Johnny, I sent you my email addy on PM. Please email pdf of schematic if you have any.

Hey there
Sorry to bother, But you were recommended over @ t4r.

Finally a reply :fro:haha...thanks for tuning in KV

 

[fourwd1]

First off, DO NOT replace an 80A fusible link with a 120A one !
Second, the A/C doesn't work because the blower isn't working, it's a safety interlock.

 

[fourwd1]

The blower motor gets its power from the alt via the heater relay and heater fuse.

 

[Jonny]

Thank for the confidence, KidV

Hi Johnny,
No bother at all. Sorry, just so busy at the office and preparing for a move. Don't have experience with the 1990 but will read/try to respond this weekend.

Does anyone have schematic for the AC system on this particular truck he can share?
Johnny, I sent you my email addy on PM. Please email pdf of schematic if you have any.

Hey there
Sorry to bother, But you were recommended over @ t4r.

First off, DO NOT replace an 80A fusible link with a 120A one !
Second, the A/C doesn't work because the blower isn't working, it's a safety interlock.

The blower motor gets its power from the alt via the heater relay and heater fuse.

The OP in the original thread(cs130 swap thread) stated that the 10ga factory wiring should be able to handle the 105amp alternator if you upgrade the 80amp to a 100amp fuse. Kind of thought- factory alternator is 60 amp with an 80 amp fuse. 20 over.. 105 amp alternator. with a 120 amp fuse.
What would be your personal suggestion to this situation then?
would a 100a fusible link blow with the 105a alternator?

 

[Jonny]

Thank for the confidence, KidV

Hi Johnny,
No bother at all. Sorry, just so busy at the office and preparing for a move. Don't have experience with the 1990 but will read/try to respond this weekend.

Does anyone have schematic for the AC system on this particular truck he can share?
Johnny, I sent you my email addy on PM. Please email pdf of schematic if you have any.

Hey there
Sorry to bother, But you were recommended over @ t4r.

thanks RAD
If i get my hands on the schem...I will fwd it to you

 

[RAD4Runner]

The OP in the original thread(cs130 swap thread) stated that the 10ga factory wiring should be able to handle the 105amp alternator if you upgrade the 80amp to a 100amp fuse.

NOT A GOOD IDEA! The 80-Amp fuse is there to protect stock wiring/circuit which is rated only for 80-Amps.
To properly use an upgrade alternator, assuming you know exactly the additional capacity of your alternator:
1) Leave stock circuit alone. Original capacity of alternator will handle it
2) Wire "auxiliary" distribution fuse block directly to the alternator using using proper wire gauge and a main fuse (similar to 80 amp Fusible Link) to handle your added capacity. Fuse should be as close to the alternator as possible. Might have to be inline fuse holder
3) Power your auxiliary devices from fuse block with proper fuses for each circuit.
4) Make sure total current draw (IF ALL AUX's ARE ON) from fuse block does not exceed your additional capacity.

Speaking of fuse block, I am actually shopping for one.
Need one that :
1) Has a buss bar that I will connect to alternator via 8-AWG wire,
2) Distributes to 6 fuses (20-Amp each).
If anyone sees one online, please advise.

 

[fourwd1]

The OP in the original thread(cs130 swap thread) stated that the 10ga factory wiring should be able to handle the 105amp alternator if you upgrade the 80amp to a 100amp fuse. Kind of thought- factory alternator is 60 amp with an 80 amp fuse. 20 over.. 105 amp alternator. with a 120 amp fuse.
What would be your personal suggestion to this situation then?
would a 100a fusible link blow with the 105a alternator?

A fuse blows when too much current is drawn thru it.
It doesn't care how much the source (alt) can supply, it's how much of a load you put on it.

If you were to put a 120A "fuse" in place of the 80A, and and draw more than 80A thru it, the vehicle wiring would melt before the fuse would blow. The current capacity of the fuse is sized for the current capacity of the wiring.

 

[Jonny]

Rad & fourwd
Thank you both.
I understand the idea of adding a fuse block powered by the alternator post but my new alternator is on only 45 A larger than the stock one.the electric fam alone pulls 40a upon start up. The way I have it set up right now is a fused 4 gauge power line from the alternator post to my battery And the charging system is working just fine my only issue is the AC not getting power. What are your guys thoughts on somehow getting 12 V to the AC & heating system? The stock alternator post wire that I snipped had two wires does one of them run to the 80a fuse and one to the AC system?

 

[helo-mech]

[MENTION=80771]RAD4Runner[/MENTION] I have the 95. Can anyone verify that it is the same? It's here in my DropBox if you want it. https://www.dropbox.com/s/1rkdm98qj672fy3/aircond.pdf

 

[fourwd1]

...The stock alternator post wire that I snipped had two wires does one of them run to the 80a fuse and one to the AC system?

The wiring diagrams do not reflect the actual way the wiring harness runs, but the blower motor and CDS fan (A/C) are among the things that could be affected.

 

[RAD4Runner]

Rad & fourwd
The stock alternator post wire that I snipped had two wires does one of them run to the 80a fuse and one to the AC system?

[MENTION=80771]RAD4Runner[/MENTION] I have the 95. Can anyone verify that it is the same? It's here in my DropBox if you want it. https://www.dropbox.com/s/1rkdm98qj672fy3/aircond.pdf

Thanks, helo-mech. I joined the two pages to show power supply clearly...

Jonny, Pls verify if same as your trucks. However, chances are power supply and concepts will be similar.

I have no first-hand experience with your gen truck, and so busy to read theory of operation, but but here's my contribution on power supply for now...

Schematic below shows that AC system takes power from 80A fusible link. (Directly from alternator would be dangerous). Test points I indicated for 12Volts. When blower switch is in LO through HI position, you should get 12Volts across relay coil (+12V at Pin 3 and ground at Pin 1),and relay should click. Then blower runs.

If relay clicks but blower does not run, one of the series resistors (very low resistance (less than an ohm each) in the blower resistor module could be open.

Best of luck.

 

[Jonny]

woaaah boy..
Got some reading/research to do.
haha
thank you so much for all the help guys!
Will get this sorted out soon. Luckily, It still runs & charges at the moment and it is not my Daily driver

 

[RAD4Runner]

woaaah boy..
Got some reading/research to do.

LOL! Yep, one of the reasons we bought simple trucks is so we can troubleshoot with our senses and a multi-meter and understand what's going. Even if we do not time nor equipment to repair something, we can tell mechs to ONLY do this or ONLY replace that; We would not be paying each time they make a wild guess.

 

[Jonny]

Thanks for all the help fellas. Got everything squared away. Went To the junkyard and tore apart the wire harness on a 4runner and noticed that the two wires coming off the alternator went different directions. One went to the factory charging system, the other was routed inside the cabin to the drivers foot area to all the relays and fuses under there. Hooked up that wire to the alternator post and left my new 4ga fused charging wire to the positive of the battery and that did the trick. Ac/heater/blower all work again and the new cs130 conversion is still charging. All done.
Moving on to the next project.

Chevy tahoe autmatic dimming rear view mirror haha
Got it at the junk yard + wire harness and temp sensor. Would be nice to have the compass and outside temp gauge in my 90 runner lol
Until next time
Happy modding