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Big Blue's HVAC Blower Issues


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Euraspark? I don't recognize that term, but then it is a new year. So please refresh my memory.

As for the ground relay, I already have it, although it isn't wired quite right. So I just need to sort that out and I'll have the ground relay that will fix that voltage drop problem - and take a load off the switch itself.

I should have posted my cleaned up version of that schematic instead of the very busy one from the '85 EVTM. In any case, your comment about G106 clicked and now I see what Bill is saying - run Ckt 57 to the ground relay and use 87A to ground it. But then you'd lose the ground to the AC clutch when the blower is in high and the relay is picked. (I'm not sure Big Blue is wired that way but will check it out when I'm "in there".)

As for someone with only Low and it won't shut off, I've slept since then and don't remember that very clearly. But that would take two problems: The function switch would have to feed power even in the off position, and either the blower would have to be bad or G701 bad. Right?

But Rene's high-only problem could be due to a blown thermal limiter or a bad G106. Does that make sense?

HVAC_Wiring_without_Relays.thumb.jpg.0dd48f69209cdaf924880390c460ef35.jpg

Gary,

In this illustration how come there's functions duplicated left and right, but no speed selector connected to the resistor pack????? 🧐

HVAC_Wiring_without_Relays.thumb.jpg.0dd48f69209cdaf924880390c460ef35.jpg

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Gary,

In this illustration how come there's functions duplicated left and right, but no speed selector connected to the resistor pack????? 🧐

That's easy. That is a work-in-progress to show how Big Blue's system works.

I took the messy page below from the 1985 EVTM and cleaned it up in several ways. First, I took out the text, which left me room for the to-be power relay that will connect to the BR/O wire between C606A and C603. Then I erased some of the O/BK wire, giving me room for the to-be ground relay.

Then things got a bit more tricky. I erased the leftmost set of wiring at C616 and slid the right wiring over since it started life as closest of the two to what BB has. But then I erased the "vacuum solepot" that he doesn't have as well as the words in the gray for CKT 348 that say it doesn't apply to a 7.5L.

As for the functions being duplicated, the HVAC switch is a 2-pole 7-position unit, with one pole controlling the compressor and the other the fan.

Sorry for the confusion. I thought I explained that it isn't done, but probably not. As said, we've been quite busy running errands and making doctor's visits, as we are again today, so I probably don't think through things I post completely. :nabble_smiley_blush:

1985-etm-page146.thumb.jpg.0e98fcd9441ce04cacf54d68ab371f3d.jpg

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That's easy. That is a work-in-progress to show how Big Blue's system works.

I took the messy page below from the 1985 EVTM and cleaned it up in several ways. First, I took out the text, which left me room for the to-be power relay that will connect to the BR/O wire between C606A and C603. Then I erased some of the O/BK wire, giving me room for the to-be ground relay.

Then things got a bit more tricky. I erased the leftmost set of wiring at C616 and slid the right wiring over since it started life as closest of the two to what BB has. But then I erased the "vacuum solepot" that he doesn't have as well as the words in the gray for CKT 348 that say it doesn't apply to a 7.5L.

As for the functions being duplicated, the HVAC switch is a 2-pole 7-position unit, with one pole controlling the compressor and the other the fan.

Sorry for the confusion. I thought I explained that it isn't done, but probably not. As said, we've been quite busy running errands and making doctor's visits, as we are again today, so I probably don't think through things I post completely. :nabble_smiley_blush:

I don't have an AC truck so I didn't realize it's a two pole Selector.

Thanks for taking the time to clear that up for me. :nabble_smiley_good:

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I don't have an AC truck so I didn't realize it's a two pole Selector.

Thanks for taking the time to clear that up for me. :nabble_smiley_good:

No problem. I'm just trying to do the best job possible on Big Blue's wiring documentation. And this area is far from good.

I have a small 3-ring binder in the truck that has owner's manuals, schematics, parts list, etc. And I'm wanting that to represent everything different. So as I find something I try to document it. I've had the passenger-side PDB's schematic in the binder for some time, but when I changed the starter wiring to use the fender-mounted relay instead of the Bosch one I didn't change the schematic.

Now I've redrawn the PDB's schematic to show the ground and power relays for the blower, but want to put this modified EVTM page in the binder as well so need to add those relays to it. But it looks like all I can do is to put simple relay outlines in it and refer the reader to the PDB drawing that will have the pinouts on the relays called out. That's because I can't get the little details to be legible in that jpeg.

Basically what I need to do is to page through the '85 EVTM and insert a page in the binder for any deviation from the EVTM. For instance, there needs to be a page for the headlights since there are relays in the PDB. And on that page there needs to be a reference to the PDB schematic in the binder.

Thoughts? Upgrades? Better ideas?

 

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No problem. I'm just trying to do the best job possible on Big Blue's wiring documentation. And this area is far from good.

I have a small 3-ring binder in the truck that has owner's manuals, schematics, parts list, etc. And I'm wanting that to represent everything different. So as I find something I try to document it. I've had the passenger-side PDB's schematic in the binder for some time, but when I changed the starter wiring to use the fender-mounted relay instead of the Bosch one I didn't change the schematic.

Now I've redrawn the PDB's schematic to show the ground and power relays for the blower, but want to put this modified EVTM page in the binder as well so need to add those relays to it. But it looks like all I can do is to put simple relay outlines in it and refer the reader to the PDB drawing that will have the pinouts on the relays called out. That's because I can't get the little details to be legible in that jpeg.

Basically what I need to do is to page through the '85 EVTM and insert a page in the binder for any deviation from the EVTM. For instance, there needs to be a page for the headlights since there are relays in the PDB. And on that page there needs to be a reference to the PDB schematic in the binder.

Thoughts? Upgrades? Better ideas?

Here's what I've created. First, is the EVTM page revised, followed by the schematic for the passengers side PDB. These would be the pages I put in Big Blue's binder. Thoughts?

Oops, I just realized that the latter doesn't show the aux battery and the smart battery isolator. :nabble_anim_working:

HVAC_Wiring_with_Relays__Gray_Box.thumb.jpg.05518234a771ace3b4ae27a67fe7eed9.jpg

PCB_Wiring_-_Revised_For_Blower.thumb.jpg.52d8a5502feeead59c69f2854c6c5947.jpg

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Here's what I've created. First, is the EVTM page revised, followed by the schematic for the passengers side PDB. These would be the pages I put in Big Blue's binder. Thoughts?

Oops, I just realized that the latter doesn't show the aux battery and the smart battery isolator. :nabble_anim_working:

Looks pretty good. FYI, if the L, M1 & M2 seem a little slow still, check the ground side for voltage drop. Whoever Ford had designing the wiring for these must have been hired from Ford of Great Britain, only thing missing is this: Rare_Lucas_part.jpg.3aeed50f6ddf35446f7b1910e028b097.jpg

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Looks pretty good. FYI, if the L, M1 & M2 seem a little slow still, check the ground side for voltage drop. Whoever Ford had designing the wiring for these must have been hired from Ford of Great Britain, only thing missing is this:

Thanks, Bill. I agree that they were on something. :nabble_smiley_what:

I've gotten quite a few of the changes documented, but have a long way to go. But I think I'll stick with the ones needed for the blower motor for the time being and then do the others later.

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Here's what I've created. First, is the EVTM page revised, followed by the schematic for the passengers side PDB. These would be the pages I put in Big Blue's binder. Thoughts?

Oops, I just realized that the latter doesn't show the aux battery and the smart battery isolator. :nabble_anim_working:

Methinks you'll be re-writing the entire EVTM, and adding an appendix.... :nabble_laughing-25-x-25_orig:

Annotations are great, but thinking about a future 'me' having to make sense of a mad scientist previous owners modifications, what would be most helpful is a accurate graphic of the entire PDC with fuses and relays called out at the margin (not unlike the graphic of my fuse panel)

You could even take a picture of it and reduce everything in greyscale, then overlay numbers or letters on that image.

You could even take a page from Ford and use F for fuse, R for relay or B for breaker

F-17 for example.....

Definitely have this on the same physical page.

Nothing is more infuriating than having to look away while you're puzzling your way though a broken (X)

The schematic is "helpful" but it doesn't help me much when I'm under the hood trying to decipher a fault.

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Methinks you'll be re-writing the entire EVTM, and adding an appendix.... http://www.garysgaragemahal.com/uploads/6/5/8/7/65879365/laughing-25-x-25_orig.gif

Annotations are great, but thinking about a future 'me' having to make sense of a mad scientist previous owners modifications, what would be most helpful is a accurate graphic of the entire PDC with fuses and relays called out at the margin (not unlike the graphic of my fuse panel)

You could even take a picture of it and reduce everything in greyscale, then overlay numbers or letters on that image.

You could even take a page from Ford and use F for fuse, R for relay or B for breaker

F-17 for example.....

Definitely have this on the same physical page.

Nothing is more infuriating than having to look away while you're puzzling your way though a broken (X)

The schematic is "helpful" but it doesn't help me much when I'm under the hood trying to decipher a fault.

Good idea, Jim, but let me see if I understand. You are talking about an outline drawing of the PDB that includes the fuses, relays, and diode with callouts telling what each does. Then that would be reduced to sit in a corner of any schematic where that PDB's components appear. Right?

I have that drawing for the driver's side PDB already, and thought I did for the passenger's side one. In fact, they were printed, laminated, and stuffed inside the PDB so you could easily see what relay or fuse does which function. But when I opened the PS PDB the other day it wasn't there. So I'll need to figure that out.

But I'm not sure about being able to make it legible on the modified EVTM's schematic. That is a low res jpg and when I put things on it they've come out really poor. So I'm wondering if I might be better off redrawing the EVTM page in TurboCAD instead of spending time modifying it to match Big Blue. That would let me print at 600 dpi and that gives good, crisp pictures.

That might actually be easier than cutting & pasting things in Paint. Looking at the schematic below, all of the fuselinks are now fuses in the PDB, the ammeter is a voltmeter and its wiring includes a relay in the PDB, and the alternator is a 3G. But I could do it in the EVTM format so it matches other pages. http://www.garysgaragemahal.com/uploads/6/5/8/7/65879365/thinking-26_orig.jpg

1985-etm-page17.thumb.jpg.6b4d39fc9d60c2b618de3eb2416c39ff.jpg

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Good idea, Jim, but let me see if I understand. You are talking about an outline drawing of the PDB that includes the fuses, relays, and diode with callouts telling what each does. Then that would be reduced to sit in a corner of any schematic where that PDB's components appear. Right?

I have that drawing for the driver's side PDB already, and thought I did for the passenger's side one. In fact, they were printed, laminated, and stuffed inside the PDB so you could easily see what relay or fuse does which function. But when I opened the PS PDB the other day it wasn't there. So I'll need to figure that out.

But I'm not sure about being able to make it legible on the modified EVTM's schematic. That is a low res jpg and when I put things on it they've come out really poor. So I'm wondering if I might be better off redrawing the EVTM page in TurboCAD instead of spending time modifying it to match Big Blue. That would let me print at 600 dpi and that gives good, crisp pictures.

That might actually be easier than cutting & pasting things in Paint. Looking at the schematic below, all of the fuselinks are now fuses in the PDB, the ammeter is a voltmeter and its wiring includes a relay in the PDB, and the alternator is a 3G. But I could do it in the EVTM format so it matches other pages. :nabble_thinking-26_orig:

No

It would be entirely separate from any schematic.

Just a page by itself with graphic proportional representation of the PDC and a legend at the side/bottom defining each component

Just like my Ford fuse box cover.

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