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[Surfnut]

Very long story short.

I have to have these two connections installed into the back of my instrument panel in order for my alternator to charge.



The wire at the bottom left (white with a black stripe) goes all the way back to the alternator.





In my build, I am using Speedhut gauges ; the XR2 instrument panel is not being used.  But I can't figure out how to get the alternator to charge without plugging in these two connectors.  Can anybody please give me a workaround?  I've got to be able to bypass something somewhere and make the alternator charge - I just don't know what to do.


Here are links to the 1991 Capri wiring diagrams.  I've looked at them for an hour and I can't make heads or tails out of it.

http://www.techcapri.com/Wiring/Capri_WIRE_91_28x17_Complete.pdf



Starting / Charging circuit, (page 10)

http://www.techcapri.com/Wiring/Capri_WIRE_91_Subsystem_Wiring_Digrams.pdf


Thank you for any help you can give me.

Dave

[chrispoe]

The white/black wire that goes to the instrument cluster is for the battery indicator lamp that illuminates when the alternator isn’t charging.

The white/red wire from the alternator needs +12V to operate the internal regulator, so wire it to the alternator’s battery output (red wire).

[Surfnut]

Okay.
So if I put an ignition switched 12V to the white/red wire, the alternator will charge when running?

Is that right?

Thank you very much for your advice!!!

[Capritain]

No one ever mention about the battery indicator when I asked for help with alternator.  So no light mean it's charging?

The white/black wire that goes to the instrument cluster is for the battery indicator lamp that illuminates when the alternator isn’t charging.

[Surfnut]

I believe that is correct. 
No battery light coming on on the dash when the engine is running means the alternator is charging.

[chrispoe]

Okay.
So if I put an ignition switched 12V to the white/red wire, the alternator will charge when running?

Is that right?

Thank you very much for your advice!!!

Yup, but I would be leery of connecting it to the ignition switch output.  If the regulator ever has a catastrophic failure (extremely rare), It could damage your ignition switch too.

I would also strongly recommend connecting the white/black wire to some sort of indicator lamp to notify you immediately of a potential belt failure. If the alternator belt breaks or comes off, then the water pump won’t be running too and the engine will be overheating.

No one ever mention about the battery indicator when I asked for help with alternator.  So no light mean it's charging?

It should, unless the bulb is out or somebody cut the white/black wire.

[Surfnut]

I just checked - the white wire with the red stripe has a constant 12V running through it.  Whether the engine is off or the ignition is on or the engine is running or not, that wire already has 12V to it.

Additionally, there is 12V to the white wire with the red stripe whether I have the two connectors installed into the back of the instrument cluster or not.

The white wire with the black stripe appears to be a constant ground as well.
 
Since the white wire with the red stripe already has a constant 12V to it, it doesn't make sense to me to put another 12V source to it.......I'm confused.  What do you think I should do?

I'm thinking the mystery lies in the connections to the I.P. ?

[chrispoe]

I’m guessing you are using the Capri’s wire harness and engine fuse box?
If you are, than you won’t need to do anything to the white/red wire from the alternator cuz it goes to the BTN fuse in the engine fuse box for its continuous +12V.

The white/black wire coming out of the alternator will be grounded when the alternator is not charging.
If you have a 168/194 bulb and socket with wires, try wiring one lead to the white/black wire from the alternator and the other lead to +12V to simulate the instrument clusters battery lamp indicator.

If the alternator starts charging, then that means two things, the alternator requires the battery lamp indicator and the wiring schematic I have has yet another flaw.

[Surfnut]

Thanks a million, Chrispoe, we got it now.

All I needed to do was connect the white wire with the black stripe to a lead from a bulb and connect the other lead from the bulb to a switched 12V source.  When the ignition is switched on, the light illuminates.  When the engine fires and the alternator starts charging, the light goes out.  Nothin' to it (now that I know!!)

Thank you again Chrispoe for all your help with this.  I really appreciate it!

The only two things I have left to figure out is where on the engine I need to connect my wire for my Speedhut tachometer and figure out where the backup light switch is. 


I found this link for a Miata backup light switch :

http://www.miata.net/garage/reverse.html

But other than that, I have no idea where it is.     Can anyone please help me with the tach wire / backup light switch issues I'm having?

Thanks again!

Dave

[chrispoe]

The tach signal can be found at a couple of locations, it’s the yellow/blue wire at the instrument cluster, ecm,  knock box, and the tach test connector.


The 2 wire backup switch is on the turbo/exhaust side of the transmission

(it’s  a pic of yours that you posted in the V6 swap thread)  The wires located in the bottom left corner of the pic should go into the backup switch on the tranny which is located just below these wires.  One wire should go to +12V switched and the other to the backup llights.

[Surfnut]

Okay, I got the backup lights working - thank you!

The tach is the last thing.  I found this yellow wire with a blue stripe sitting here.  Can I get a tach signal from here?



It has the white plastic connector on the end of it:




Thank you again for your help!

Dave

[chrispoe]

Yes, that’s the tach test connector

[Surfnut]

WOO HOO!!   WE GOT TACH!!!   


Thank you very much Chrispoe!   I really appreciate your knowledge and help.


Thank you again,

Dave

[Gaz]

Thanks a million, Chrispoe, we got it now.

All I needed to do was connect the white wire with the black stripe to a lead from a bulb and connect the other lead from the bulb to a switched 12V source.  When the ignition is switched on, the light illuminates.  When the engine fires and the alternator starts charging, the light goes out.  Nothin' to it (now that I know!!)

Thank you again Chrispoe for all your help with this.  I really appreciate it!

The only two things I have left to figure out is where on the engine I need to connect my wire for my Speedhut tachometer and figure out where the backup light switch is. 


I found this link for a Miata backup light switch :

http://www.miata.net/garage/reverse.html

But other than that, I have no idea where it is.     Can anyone please help me with the tach wire / backup light switch issues I'm having?

Thanks again!

Dave

Say, did you have to wire in a diode to your alternator fix? I see that there is one on the diagram, on the IP board housing the charging lamp.