I'm having issues with my PJB. The interior lights and running lamps wont turn on without messing with the PJB. I've narrowed it down to the TNS relay but don't really feel like paying over $1000 to fix it. Does anyone know of a way to bypass the PJB relay for this issue? Can I hook up an external relay? What exactly would need to be done?

 

if they relay went bad, it is possible to replace it. From what i've seen on the PJB failures it's water damage - is that the case with yours? or haven't you pulled the PJB apart to see what's going on?

I forget what all the TNS relay drives, but i'm sure there's a way to bypass it and at least keep most of its functionality. I'll try to remember to look at my wiring diagrams when I get home...

 

It doesn't appear to be water damage by looking at it. I have taken the PJB out but replacing a relay doesn't look like an easy task. The PJB is two boards that are soldered together at many points on the outside edges (close to 100 if I counted right). I'd probably mess something up seperating the boards and then re-joining them. Not to mention I'm not sure which is the TNS relay. If you could find a way to bypass it, at least for the running lamps and interior lights I would GREATLY appreciate it!

 

Have a look at the 3rd pic at https://www.mazda3club.com/showthrea...t=44332&page=2
that's got a pic of the connectors and pin numbers i'll reference below.

The TNS relay is driven from a logic circuit on the PJB board, but it is what switches all the illumination on the dash (F82) and tail lights (F81, F46). If you have all those going on/off at once - it's the relay, otherwise it could be just one of the fuse connections.
TNS is powered by F3 on the main fuse block, and connects to the PJB on J-01 pin F (pink with a blue stripe), and connects to the three fuses noted above.
F82 is connected to J-03 pin H (orange wire with blue stripe)
F81 is connected to J-01 pin AC (orange with blue stripe) as well as pin G (orange with white stripe)
F46 is connected to J-01 pin K (orange with blue stripe) as well as pin AS (orange wire)

Hope this is enough information to help, let me know if anything else is needed.

 

ah, and the ignition switch feeding the logic there is coming on J-03 pin AP (grey wire with a yellow stripe. This should be used to trigger the replacement TNS relay.

If the relay isn't coming on, you can try to measure the coil voltage to see if it's being turned on or if the relay contacts are stuck. You could wire another relay in parallel with the TNS that's already there, though that can cause other issues too.

 

Thanks for the info. I'm still a little confused as to what I would attach where on the new relay. Should I use diodes anywhere? What relay should I use? Thanks again for the help!

 

the relay common (contacts common) should attach to the power in from F3
the relay output (NO = normally open) contact should connect to the power side of the 3 fuses
The relay coil should connect from ground to the ignition input (J-01 pin F) which will turn on relay power. the relay coil in this circuit doesn't really need a diode on it, but in general there should be one across the relay coil to prevent high voltage when the coil is turned off. A 1N4004 diode with the stripe on the 12V side of the coil will prevent the voltage spike.
As for what relay, a standard 30A bosch automotive relay should work fine, they are easy to find at radio shack, walmart, or a stereo install shop.

To do it 'best' the 3 fuses should be pulled and put in an external fuse block. This would disconnect the existing TNS relay from powering the lights, so it can't cause any problems.

 

I think understood part of that. Let me run through it just to make sure. I’ve got a few of those relays lying with the wiring pigtails so I should just need to buy a diode. I uploaded a diagram for the relay to reference.

Terminal 30 should be fused and connected to the battery or another 12V constant.
Second, the power in from F3 should connect to terminal 85 on the relay, right? But which wire is that?

Next, cut the three wires leading to “H” on J-03 and “AC”, “G”, “K” and “AS” on J-01. Remove their respective fuses from the PJB and install them in an inline fuse assembly. Wire each fuse assembly to the respective cut wire(s). Then, the fused side of each wire should connect to terminal 87 of the relay.

Lastly, I should cut the wire feeding to pin “F” on J-01 and connect it to terminal 86 on the relay. The diode should connect terminals 85 and 86 with the stripe closest to terminal 86.

I’m guessing I probably botched up what you said entirely and I apologize if I did. Thanks again for all of your help, I can’t thank you enough!

 

Yes, that's the standard relay I was thinking of... it's possible that it has a diode already in it, see if 85 & 86 are labeled as + - or if the little schematic symbol on the relay shows a component across those pins.

Don't cut any of the wiring, you can just tap onto all of it... at least until you make sure that everything is working properly.
For putting power back into the system through the relay, use a blown fuse, solder a wire on one end, and plug into the proper fuse location (F46, F81, F82 - or the appropriate wire if you wish)... then attach that to whatever you're using for a fuse block from the relay.

Pin 30 should connect to the PJB on J-01 pin F (pink with a blue stripe), this is already a fused connection (F3). This wire should be stripped and soldered onto, don't just cut it since it powers other stuff in the PJB.

One of the coil pins should connect to ground - use any close chassis bolt that's already got a wire connected as a ground, and conect the other coil pin to switched battery = ignition input *mistake* (J-01 pin F) *mistake* **correct** J-03 pin AP **correct**

I'd just pull the 3 fuses, not cutting any of the wiring, and attach them all with a seperate fuse block (or just solder them in for testing) and connect to pin 87 - which will be switched power for all the lighting.

Does this make sense?

 

I think I got most of it.

If my relay shows a + - on 85 & 86, it already has a diode so I don’t need to install one.
Pin 30 goes to “F” on J01 but should only tap into it as the wire is needed for other applications.

Next, one end of the coil goes to an existing ground and the other end connects to “F” on J01 as well. Again, not cutting the wire because it’s needed to power other things.
Instead of cutting the five wires going to the three fuses, I should just pull the fuses because it would essentially do the same thing. Then tap into the wires mentioned, fuse them and wire them to terminal 87.

No connection at terminal 87a.

The only part I didn’t understand was using a blown fuse to put power back into the system through the relay.

 

Getting very close
The coil shouldn't connect to pin F, since that's constant 12V, That was my mistake writing above... it needs to connect to a switched 12 v source, which is J-03 pin AP.
As for polarity, I didn't see that you have written on the relay diagram above that pin 85 is ground and 86 is the feed - this is what should connect to J-03 pin AP.

Concerning the blown fuse... if you use a good fuse, it connects both ends of a wire basically, allowing power to pass through. I you use a blown fuse and solder a wire on one of its legs, it's the same as stripping and connecting to the wire where it's coming out of the connector (J-01 etc...). So if you want a permanent connection, you can solder onto the wiring directly. But for testing to make sure everything is going to work ok, use an old fuse so you can plug it in instead of screwing with the wiring harness on the car.

 

Sorry I haven't responded in a while but I was out of town all weekend. I understand what you mean by using a blown fuse now.

This is the relay I'm working with:

http://www.sonicelectronix.com/item_...mpaign=froogle

It doesn't look like it has a diode built in so I'll have to pick one up.

Let me go through it one more time before giving it a shot.


Pin 30 goes to “F” on J01 but should only tap into it as the wire is needed for other applications.

Next, 85 connects to a ground and 86 to “AP” on J03. Again, not cutting the wire because it’s needed to power other things. A diode should be installed between 85 and 86 with the striped end closer to 86.

Then, take blown fuses and solder a wire to one of the contacts, making sure that when plugged back in, that contact is on the powered side of the fuse. Then take those three wires from those fuses and solder them to terminal 87

No connection at terminal 87a.

Does all that sound right?

 

Also, with 85 connecting to "AP" on J03, that means the interior lights and parking lamps would come on when the ignition is turned to "on", not with the original factory controls, right?

 

Yes, that sounds like it.

I didn't think about the factory light control - i'll have to look at what that switch goes to normally. It is probably a switched ground, so that would connect to the relay coil pin 85 instead of going directly to ground... i'll try to remember this tonight when I get home.

 

Thanks again!