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  #1  
Old 19th March 2008
blunk_blind blunk_blind is offline
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Default APC solenoid question

I have been experiencing base boost, so i decided to look into it.

My APC solenoid is not get any power. However it is getting ground.

I just took a test light connected it to the battery to test (with the ignition on) the connector that plugs into the solenoid. I got a light on ground but no light on the power. My question is

Where does this wire go too? (the yellow one)
How do I fix?

thanks
Kyle
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  #2  
Old 19th March 2008
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grif900 grif900 is offline
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I dont think the apc solenoid should get power all the time, and if it did you would have to hook the clip on the test light to the neg. terminal on the battery to look for it first.
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Old 19th March 2008
blunk_blind blunk_blind is offline
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Quote:
Originally Posted by grif900
I dont think the apc solenoid should get power all the time, and if it did you would have to hook the clip on the test light to the neg. terminal on the battery to look for it first.
townsendimports.com says the following from thier diagnosis of base boost apc section.

"Second, listen for a click from the solenoid valve when the key is turned on. The APC should send power to the solenoid and it has a permanent ground, so with the key on, one audible click should come from it. If not, check the fuses and then the wiring to the APC solenoid. One wire should have 12V with the key on and the other ground. Check each one for shorting to ground or power. It is common for them to lose their insulation and keep the solenoid from energizing. "

I did hook the test light to the neg terminal when checking for 12V on the apc solenoid connector. My APC solenoid does not click either when the car is turned on ignition.

Does anyone know when the APC solenoid needs power? And where does it get its power from??

Last edited by blunk_blind; 19th March 2008 at 07:58 PM.
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  #4  
Old 19th March 2008
Paul92Conv Paul92Conv is offline
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The Townsend site also show's a wiring diagram take a look.
http://townsendimports.com/Web/elect...r/89apcwir.htm

The APC solenoid is 179 so it gets it's power from the APC Control Unit on the left front fender.
Also note that if you have Cruise that power wire goes through a vacuum switch 233 which is also in the left front fender area.
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Old 19th March 2008
blunk_blind blunk_blind is offline
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Quote:
Originally Posted by Paul92Conv
The Townsend site also show's a wiring diagram take a look.
http://townsendimports.com/Web/elect...r/89apcwir.htm

The APC solenoid is 179 so it gets it's power from the APC Control Unit on the left front fender.
Also note that if you have Cruise that power wire goes through a vacuum switch 233 which is also in the left front fender area.
I noticed the wiring diagram, but have no idea on how to read one. Thanks for pointing out that the power is 179 though, makes a little more sense. I have been reading for about the past 2 hours through the forums and 900aero about this problem. I ran across someone that just gave direct power to the APC solenoid from the battery, i dont know if this is proper or not though? My cruise dosent work either, dont know if this is a problem, i dont care either if it does..

thanks
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  #6  
Old 19th March 2008
Paul92Conv Paul92Conv is offline
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No the solenoid does not get constant power but gets power in the forum of a signal from the Control Unit based on inputs from the knock sensor and the pressure transmitter.
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Old 19th March 2008
blunk_blind blunk_blind is offline
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Quote:
Originally Posted by Paul92Conv
No the solenoid does not get constant power but gets power in the forum of a signal from the Control Unit based on inputs from the knock sensor and the pressure transmitter.
So to fix this, i have to pull off the plug from the apc unit, run a wire from pin 12 to the solenoid, and if that works great. If I am not getting power from the apc unit pin 12, this means that i am in a whole bunch of new problems: knock sensor could be faulty, apc box is bad...the list goes on.

thanks for all your help
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  #8  
Old 19th March 2008
Paul92Conv Paul92Conv is offline
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I would just tap into the wire (yellow with a white tracer) close to the Control Unit then check for a signal. If you have a signal then just cut and run a new wire from were you tapped into it to the solenoid. This will also bypass the cruise vacuum switch which you don't care about anyway.
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  #9  
Old 20th March 2008
blunk_blind blunk_blind is offline
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After dismantling the apc and figuring out which pin is which i tested (with test light) a few of the pins to make sure that the APC box was getting the right reading.

I have the 25 pin connector.
Brake pin is correct, light comes on when brake is pushed (and is not on when brake is not being pushed)
Ground and 12V come on.
Have not performed a knock test yet

I still dont understand on how to check pin 12 (the 12V wire that leads to the solenoid) however. What check method should i be performing? I am going off the assumption that you need 12V power to the APC solenoid when the car is on ignition. (as well as it clicks which i dont have either)

Do you have to check pin 12 with the box plugged in? I would think so but how do you do that?

I am new to all this APC stuff, so please to bash me for being a little slow.

Last edited by blunk_blind; 20th March 2008 at 12:40 AM.
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  #10  
Old 20th March 2008
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cdaly cdaly is offline
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Check pin 12 with the box plugged in and the ignition on. Use the test light from pin 12 to the battery ground. If you get 12V there, the problem is probably the cruise vac switch. Jump the contacts on that and the solenoid should click. If that works, you can leave the jumper in place to bypass the vac switch. However, if you should get around to fixing the cruise system, you should fix and reconnect the vac switch...


The easiest place to check pin 12 would be at the cruise vac switch since the wire goes directly there from the APC box and you should be easily able to get at the terminal there. If not, peel back the rubber boot from the connector at the APC box and access pin 12 from that side. Make sure you seal it up well afterwards to keep water out.
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  #11  
Old 20th March 2008
blunk_blind blunk_blind is offline
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Quote:
Originally Posted by cdaly
Check pin 12 with the box plugged in and the ignition on. Use the test light from pin 12 to the battery ground. If you get 12V there, the problem is probably the cruise vac switch. Jump the contacts on that and the solenoid should click. If that works, you can leave the jumper in place to bypass the vac switch. However, if you should get around to fixing the cruise system, you should fix and reconnect the vac switch...


The easiest place to check pin 12 would be at the cruise vac switch since the wire goes directly there from the APC box and you should be easily able to get at the terminal there. If not, peel back the rubber boot from the connector at the APC box and access pin 12 from that side. Make sure you seal it up well afterwards to keep water out.
I have a red-caped vac swich, it has two wires going into it, to understand what your saying, I should (for testing purposes) pull the plug out of the bottom of the vac switch and connect the two wires together and that will bypass the cruise. And for more confirmation - Does the flow of current go from the 12V in to APC > to pin 12 > to the cruise vac > output to the solenoid?

thanks


I just went and tried that out, i yanked the connector on the curise vac, i didnt know which one went to the solenoid and which one went to the apc box, nevertheless i tried both. First of all i dont get 12V from either of them when the engine is turned on. which is a problem

I spiced the wire from the solenoid (yellow one), wrapped a wire around the spiced section then jammed the other end of my jumper wire into the connector of the cruise vac, hoping for a miracle. (my solenoid does work by the way, i just tested it out)

So my question is what is causing pin 12 to fail on the APC box?

Last edited by blunk_blind; 20th March 2008 at 10:20 AM.
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