Big Blue's Transformation

[85lebaront2]

Gary, if you are using the '96 front wiring harness (mostly) I would definitely stick with using the Bosch style relays. They are plentiful, I have a huge box full of them, all tested (both NC and NO contacts and coil) I also have found that Ford, GM and Chrysler use the same relays but each has their own PN for them.

On Darth, I grabbed a auxiliary relay box from a Bronco that has 4 Bosch relays in it, it was for part of the ABS and trailer package. I have 3 relays for the trailer lights + the battery charge relay. I wired the trailer stop and turn using the '96 harness, but modified by taking the rear stop and turn trailer feed Ford provided and using the taps that went to the two fuses for the trailer option but tapped into the circuit ahead of the fuses, used that for my trailer stop and turn relay coils, took the NO contacts output back through the fuses and into the '96 trailer harness. This way all of my rear clearance lights and trailer running along with stop and turn lights are isolated through fuses so a short in a trailer will not take out my truck lights.

I can mark up the required pages from a '96 EVTM later, I will be gone most of the day.

[Gary Lewis]

Jim - No, the '96 PDB doesn't have a relay for the blower motor.  And while I'd like to do that it isn't on the list for right now.  A wise man recently said "A man has to have his priorities."    (But, if I ran across the 4-relay box Bill mentioned I could use that for the headlights and the blower motor.  Hmmm.....)

Bill - Since you've done it, meaning the "use G112" trick, it is good to see you say "use the Bosch relays".  That trick is neat, but going with the FPR in the PDB has a lot of merit.

And while some may think that having made the decision I no longer need to draw up the change.  But I want to see it on "paper", and I want to leave it for posterity.

As for the trailering package, I think that's where I'll draw the line on what gets integrated from the '96 harness.  The '85 setup, ugly as it is, works.  So I think I'll leave it in place and use that time to get other things done.

[Gary Lewis]

Ok, let's try this.  Here's the '96 wiring on the left and the '85 wiring on the right:




And this shows what I plan to do, but w/o taking out the extraneous stuff:




Last, this shows the resulting wiring with the extraneous stuff gone:

[ArdWrknTrk]

Challenging to view on my phone.
I get the gist of what you're doing with the PCM to drive the pumps.

Side note to my suggestion above, I see that wire colors swap at my blower motor connector.


I seem to have just enough 10Ga primary wire to reach there and back, though I only need milliamps to close the relay, it is on a 30A fuse in the truck, and should probably be rated for that.

[Gary Lewis]

And now for a potential modification of the starter relay plans.  I found that I have the box below, which has four relays.  Three are the standard Bosch 40 amp relays, but the fourth is a 70 amp job with the big terminals, as shown on the spare relay below the box.

So, instead of the fender-mounted starter relay, how 'bout a stud to take the charge cable from the alternator, the battery cable, the fuselinks to the Bullnose wiring, and the cable running across the radiator support to the PDB.  And then use this box for two headlight relays, the blower relay, and the 70 amp relay to pull in the starter.

The downside is that this box doesn't have any positions for fuses and I need a fuse for the headlights.  Having said that I do have an auto-reset circuit breaker that I used previously on the headlight wiring harness and it would work just fine, although not as elegant as a slot in the box.

What'cha think?

[Gary Lewis]

Yes, if you leave the 30A fuse in the box you'll need to use wiring capable of handling that current.

[ArdWrknTrk]

Since I'm using a 40A relay to activate my starter solenoid, I can't see the need for 70.

I'd probably use 87a for low and 87 for high.
Why would you need two?

My, that's a big blade on 30!
Maybe it is used for electric fans?

[Gary Lewis]

Yes, it is a BIG blade, on both 30 and 87.  And while 40 amps is obviously adequate, there no downside to 70 amps of capacity.  

[Gary Lewis]

Missed the bit about 87 and 87a.  Need one relay to put power to that one.  Or, one each for high and low.  How do you do it?

[ArdWrknTrk]

As said above, you'll need a cable capable of 70A just to drive the solenoid of the starter.

That seems a bit absurd to me if the solenoid only requires 13A to hold.

[ArdWrknTrk]

Also see recent comments about finding lugs small enough to even fit on the PMGR.

[Gary Lewis]

I think we may be typing at cross-purposes.  I'll use the 70a-capable relay just like you are using the 40a-capable one.  No need for a great big cable from it.  What did the factory use?  10 gauge?

For documentation purposes, here's what I found, with the box being laid out this way.  But note that Relay #2 only has small wires to/from its 30/70 terminals.  That will have to be changed to use it for any of the uses I have planned.

  _____________
  |                      |
  |  #2       #1     |
  |                      |
  |   #3      Big    |
  ------------------

Big Relay:
30 = R/Bk - large
87 = R/LB - large
85 = Gn/Bk
86 = R/Bk - small  (Note: There are two small R/Bk wires)

#1 Relay:
30 = Y/Bk - large
87 = Blue - large
85 = R/Pk
86 = R/Bk - small (Note: there are two small R/Bk wires)

#2 Relay:
30 = Y/DG - small (Note: this goes to 86 also)
87 = Y/LG - small
85 = DB - small
86 = Y/DG - small (Note: this goes to 30 also)

#3 Relay:
30 = Bk/LG - large
87 = Y/LB - large
85 = Bk - small
86 = WPk - small                |

[ArdWrknTrk]

I think it might have been 12.
I guess it depends on what you choose to feed that relay.

I have a 6Ga. Bus coming right off the Megafuse, so I'd need to put it through a 40A fuse on the output.

I'm assuming #70 is a Ford convention?
And this = 87 on a Bosch?

[ArdWrknTrk]

What's the point of#2?

Doesn't make sense to me.

[Gary Lewis]

My bad!  I fixed it.  Should have been 87, not 70.  

And you have a good point about fuses!  I need one for the two headlight relays, one for the starter relay, and one for the heater relay.  Sure would be nice to find a box with room for those relays and fuses.  I think I'll keep looking.

But, I have no idea what the purpose is for #2.  It had to have been just to provide a signal.

[ArdWrknTrk]

Gary Lewis wrote

I have no idea what the purpose is for #2.  It had to have been just to provide a signal.

But if you're using the same wire to trigger and power the relay, what is it's purpose?
Convention has 85 trigger and 86 ground.
So 85 pulls 87 low?

[Gary Lewis]

I don't know, Jim.  Makes no sense to me.  I tried to figure out how it could be a latching relay, but failed.

But, let's talk about what I did today toward assembling Big Blue.  Very little.  I spent quite a bit of time figuring out how that relay box is wired, only to realize that w/o fuses it won't work.  

So I'm back to fleshing out Plan A - using a fender-mounted starter relay, no blower motor relay, and the headlight relays in the PDB.  Which means I'll have to populate the 5th relay position.  And I'll use the 30A auto-resetting breaker I have from another Ford PDB to replace a fuse to power the headlights.  Power to the right headlights will run across the radiator support.

Given that, we are back to an easy interface - the fuselinks, save for Fuselink S to the inertia switch, will connect to the battery terminal on the starter relay.  And, speaking of that, the ECU wants to know when the engine is cranking.  So I'll do that via the red/light blue wire that's already in the harness crossing the radiator support.  It will get connected to the red/light blue wire in the '85 wiring right there at the starter relay, thereby telling the ECU when the engine is being cranked.

And, I tried to update the BIOS on the computer, to no avail.  So tomorrow I'm going to Best Buy to see what they have.

Last, the seal came in for the spindle so I installed it using the press.  Don't know why I didn't do that before as it sure made it easy.  Then I installed the seal on the axle and slipped the spindle in place - with plenty of anti-seize 'twixt it and the knuckle to ensure it isn't rusted to it again should I need to take it off.  But, I still can't find the nuts that hold the spindles to the knuckles.  

[ArdWrknTrk]

Did you look in your powder coat oven?

[ArdWrknTrk]

I'm surprised you don't build your own shop computer, and do some things to harden it against dust and grit.

But then it was pointed out recently that YOUR shop is more of an operating theater, and doesn't see that much abuse.

[Gary Lewis]

I didn't look in the oven, but you may be onto something.  I may have PC'd them and then put them in the bag with the other PC'd but unused parts.  (I know that's not what you meant.  )

As for building my own computer, in a way I did on the one that failed.  I added a solid-state drive and a graphics card with two HDMI outputs.  But, I just saw on TV an advert for a custom computer-building outfit that is between me and Best Buy.  So I'll stop there tomorrow.  The requirements are a solid-state drive and a graphics card with two HDMI outputs.  Doesn't have to be blindingly fast, but does need to have adequate memory.

As for how clean the shop is, you've been mislead.  The blast cabinet creates a fine dust that escapes the dust collector and gets everywhere.  So it would be helpful to have some kind of filtering on the computer.  But this one ran for many years with no problems.  In fact, it runs Win 8.1 and that was released Oct 17th, 2013, so it is probably seven years old.  I wonder if the dust is why it suddenly shuts down?