PCM help and monitoring water temp and oil pressure

[derotoreut]

Originally Posted by bigmoe

So if you're going with the Bim module you won't need some of these, ie. tach,
speedo, check engine. (as someone was saying). The Bim will read them from the ecm via the obdII. Have you got an LS conversion brake light switch like I have pictured? You need to run that brake wire to it.

I recently did a whole truck wiring LS conversion on my 65 C10. I'm just as intimidated by wiring as you are. One step at a time. Divide it in sections. Make notes. Tape and mark the wires as you go so you can go back and remember what you did and what for. You can remove the tape after. I had a lot of unneeded circuits in my fuse box I was able to borrow for other things.

I do not have that brake switch. I've seen it before, but for some reason I thought it was required only for cruise control. I had no idea I needed that design for my swap. Thank you so much for sharing. Now where do I get one like that?

Thanks for the vote of confidence for the wiring. I've started taping some of the leads. I'm sure I'll have some questions for you guys along the way.

[derotoreut]

My PCM harness did not have a connection for the factory oil sender, nor was there a sender anywhere. The tapped hole at the back of block was empty with nothing installed. I used that location to install the DD oil pres sender. I have no idea what the factory sender or plug even looks like for this 5.3L. Lol. Since there was no option in my harness I assumed I was supposed to use the DD oil sender. I also was unaware of the option to locate it at the oil filter. Had I known that I think I would've used that location instead.

[bigmoe]

Originally Posted by derotoreut

I do not have that brake switch. I've seen it before, but for some reason I thought it was required only for cruise control. I had no idea I needed that design for my swap. Thank you so much for sharing. Now where do I get one like that?

Thanks for the vote of confidence for the wiring. I've started taping some of the leads. I'm sure I'll have some questions for you guys along the way.

Your TCC wire goes to that switch for the torque converter clutch. Most LS swap suppliers sell them just make sure you buy one that shows what wires to hook where to make it easier for you.

[derotoreut]

Originally Posted by bigmoe

Your TCC wire goes to that switch for the torque converter clutch. Most LS swap suppliers sell them just make sure you buy one that shows what wires to hook where to make it easier for you.

So is the TCC wire the one labeled "Brake Switch" in the picture in post #5?

[derotoreut]

So I ordered the Dakota Digital BIM-01-2. With that I should not need to install the additional DD water temp sender correct? Factory water temp sender in DS head will be adequate?

Also, looking at the pictures in Post #5 of wires from my Tilden harness, do I only need to connect the "12V switched" and "Brake Switch" wires?

[70c10resto]

Originally Posted by derotoreut

So I ordered the Dakota Digital BIM-01-2. With that I should not need to install the additional DD water temp sender correct? Factory water temp sender in DS head will be adequate?

Also, looking at the pictures in Post #5 of wires from my Tilden harness, do I only need to connect the "12V switched" and "Brake Switch" wires?

That’s correct, the only additional sensor you will need is the oil pressure. I got my brake switch from bp automotive, and that looks to be correct on the wire labeled “brake”. My harness had a connection for constant 12v and it was a ring terminal that connected to the starter as well as the switched power, fuel pump, and tcc (brake) connection.

[bigmoe]

Originally Posted by derotoreut;8690441

I think I read somewhere too that guys were using some kind of splitter. I think it was for this connection into the OBD-2 port. It sounded like it created some kinds of issues (worked or didn't work), I'm not exactly sure.

[ATTACH

1988529[/ATTACH]

I just wanted to address this question because no one answered it (I think). Your Bim plugs into your OBD port. I have read that others have tried to use a splitter to give two OBD ports and allow you to hook up a scanner tool but that it would not work both scanner and gauges via Bim at the same time. So I’ve always assumed you have to unplug your Bim if you want to use a scan tool. Others might be able to clarify this for us.

[derotoreut]

Ok so this might be a stupid question, but in my post #5 picture... is the "12V Switched" wire get connected to 12V, or is it already a 12V switched line? This is how bad I am with this stuff. I just want to make sure that on the LS swap brake switch that I'm not supposed to connect the "Brake Switch" wire to the one terminal and the "12V Switched" to the other terminal.

[ls1nova71]

Originally Posted by derotoreut

Ok so this might be a stupid question, but in my post #5 picture... is the "12V Switched" wire get connected to 12V, or is it already a 12V switched line? This is how bad I am with this stuff. I just want to make sure that on the LS swap brake switch that I'm not supposed to connect the "Brake Switch" wire to the one terminal and the "12V Switched" to the other terminal.

What do your directions say? Generally one labeled 12v switched would be what you hook your ignition switch to to power up the LS harness. However, there is an off chance that it is the 12v wire that needs to be hooked up to the brake switch opposite of the purple wire, since it will need 12v. Most harnesses dont include that though, and I would think it would be labeled brake switch also, so likley isn't the case.

[derotoreut]

Originally Posted by ls1nova71

What do your directions say? Generally one labeled 12v switched would be what you hook your ignition switch to to power up the LS harness. However, there is an off chance that it is the 12v wire that needs to be hooked up to the brake switch opposite of the purple wire, since it will need 12v. Most harnesses dont include that though, and I would think it would be labeled brake switch also, so likley isn't the case.

No instructions came with it. I was told by Tilden it's "All self-explanatory". I would assume this wire needs to be connected to a 12V switched source. Hopefully that's correct.

[bigmoe]

Originally Posted by derotoreut

No instructions came with it. I was told by Tilden it's "All self-explanatory". I would assume this wire needs to be connected to a 12V switched source. Hopefully that's correct.

I would assume you hook it to a 12v switched source as well.

[ls1nova71]

Originally Posted by derotoreut

No instructions came with it. I was told by Tilden it's "All self-explanatory". I would assume this wire needs to be connected to a 12V switched source. Hopefully that's correct.

Since it doesn't say anything else, I would say you are right. You will however need to add the 12v switched wire to the other side of the brake switch for the TCC lock up.

[derotoreut]

Originally Posted by 70c10resto

That’s correct, the only additional sensor you will need is the oil pressure. I got my brake switch from bp automotive, and that looks to be correct on the wire labeled “brake”. My harness had a connection for constant 12v and it was a ring terminal that connected to the starter as well as the switched power, fuel pump, and tcc (brake) connection.

Interesting... I don't recall seeing a connection for constant 12V on my harness. There is however a ring connection for the alternator. Could that be it? I also have this harness wire "12V Switched" that I'm assuming I need to connect to a 12V switched source.

Another point I have though, is that I also have a fuel pump wire, which I assume to be power for the fuel pump? It's an extremely small gauge wire and nothing like the leads coming off of my fuel pump. Not even close. Is that OK?

[clay68c10]

The fuel pump wire is probably a trigger for a relay

[derotoreut]

Originally Posted by clay68c10

The fuel pump wire is probably a trigger for a relay

What leads me believe that it's not some sort of trigger wire is that it's an extremely long wire. Reaches all the way to the back of the truck. Maybe these pictures will help? Then someone can help me understand.

Here are the relays and fuses provided with my harness.

[First c10]

Hey Dan,
Since I only built my own harness hard for me to say but looking at the harness you have and if it came with the pictures shown I would assume that the wire for the fuel pump is probably a #12 wire minimum and long enough to reach a in-tank fuel pump. I would say that's the supply not the trigger. The fuel pump trigger was a #18/20 gauge green wire from the ECM.
That harness should have these connections to the harness the system grounds, constant 12+ and switched 12+, and these to be terminated at there locations brake pedal wire, tach wire, fuel pump supply, high and low fan supply.
oh and Check engine light!!

[bigmoe]

Originally Posted by derotoreut

Interesting... I don't recall seeing a connection for constant 12V on my harness. There is however a ring connection for the alternator. Could that be it? I also have this harness wire "12V Switched" that I'm assuming I need to connect to a 12V switched source.

Looks like the ring connection that says "alternator" will be the main 12v constant feed for your harness. That post on the alternator is hot all the time.

For the "12v switched" you want to pull from a power source that is dead when the key is off, hot with the key on. I think it has to be hot when the key is in the start position too so watch that.

[bigmoe]

Originally Posted by derotoreut

What leads me believe that it's not some sort of trigger wire is that it's an extremely long wire. Reaches all the way to the back of the truck. Maybe these pictures will help? Then someone can help me understand.

Here are the relays and fuses provided with my harness.
Attachment 1990455

Attachment 1990456

Tilden has set up a nice relay/fuse block for you. Just run that long wire to the + on your fuel pump.

[plumber452]

I see in post #23 you show the terminals labeled on the brake switch. Is the one that says PCM the TCC wire?

[plumber452]

Sorry guys. I hadn't read through the entire thread before I asked that.

[plumber452]

Sorry guys. I didn't read through the entire thread before I asked the question

[ccautoupholstery]

Originally Posted by mongocanfly

Most of us drill and tap the pass side head, at the rear, to npt, for the water temp to the gauges...
The ecm needs the sender that's on the driver side..for fans and etc..
Oil pressure can come from the rear of the engine..same location as a sb..you need a metric to npt adapter...ecm doesnt need to see oil pressure...

I just learned that you can use a stock temp sensor and connector for say a 99 Camaro that is 3 wire. It replaces the one in the drivers side and your 3rd wire (green) goes to your gauge. For me I would rather do this than tap the passenger rear.

[derotoreut]

OK so here's what I've learned today: I was able to reach Tilden. The ring terminal for the alternator is the constant hot. The wire labeled "12V Switched" needs to be connected to a 12V switched source (and it's not already a 12V switched wire). The fuel pump wire is not a trigger but the supply for the fuel pump. Tilden said it's not a problem that the supply wire is a smaller gauge then the fuel pump.

[ls1nova71]

Originally Posted by derotoreut

OK so here's what I've learned today: I was able to reach Tilden. The ring terminal for the alternator is the constant hot. The wire labeled "12V Switched" needs to be connected to a 12V switched source (and it's not already a 12V switched wire). The fuel pump wire is not a trigger but the supply for the fuel pump. Tilden said it's not a problem that the supply wire is a smaller gauge then the fuel pump.

Sounds like you're on the right track. The fuel pump wire in newer trucks are pretty small compared to most aftermarket and high HP parts.

Originally Posted by ccautoupholstery

I just learned that you can use a stock temp sensor and connector for say a 99 Camaro that is 3 wire. It replaces the one in the drivers side and your 3rd wire (green) goes to your gauge. For me I would rather do this than tap the passenger rear.

This only kind of works. Generally the resistance is off by enough to only give a vague reading of what the engine temperature actually is. You're usually best off using the sender made for whatever gauge you are using.

[LS short box]

Make sure your 12 volt switched has 12 volts with the key in the start and run position. The brake light switch needs two set of contacts. One for the normal brake light operation and for the torque converter lock up. I typically use a 2002 Camaro switch for an automatic.