About to Gut Wiring, Cut Holes in Floor & Flintstone it

[AKA3Toes]

---I've just picked up a replacement relay for the fans, as well as ordered (for a second time) the repair connector. The system cancelled my original order, so now I am waiting two more* days before installing this... which gives me time to think/ponder.

---I have:
-New Radiator Fan Motor/Air Conditioner Control Relay:
Motorcraft ............ E4DZ8B658A, E4DZ8B658B, E4ZZ8B658A, E4ZZ8B658B, E5SZ8B658A, E5ZZ8B658A, E6SZ8B658A, E6SZ8B658B, E6ZB8C609AA, E6ZZ8B658A, E7GZ8B658A, E7ZB8C609AA, E7ZZ8B658A
Airtek/Wells ......... 1R1764
GP Sorenson ........ MR-121 / MR121
Duralast .............. 20416
SMP .................... RY224

-New Relay Repair Connector:
Motorcrafy ........... E4FZ8C290A
Airtek/Wells ......... 1P1096
GP Sorenson ........ MR-242 / MR242
SMP .................... S549

-Two, 30A ATC (blade type) Circuit Breakers

-Pack of female blade/quick connectors w/heat shrink

---My original thought was to wire the circuit breakers in-line on the wires that showed heat damage... but that doesn't look feasible at this juncture cause after getting down and looking at the attached wiring diagram, it appears the two burnt wires were both switched from ignition and Battery (+)... so what gives? I thought I'd see two relays and the same terminal burnt on both (E.G., 1 & 5, 2 & 6, etc.), but that isn't the case. If that were the case, I would have even thought of wiring two separate Bosch 12v ISO 30A/40A relays in... ~INSERT: pulling out hair smiley~

---Now, the thinking part... as per my first question posted here (was wrong section & deleted); I have no radio, no diode installed to replace the one shown in the "schematics", no idea how to hook up an `88 Mustang's radio wiring without the OEM radio, but my dash lights didn't work and I suspected it had to do with the missing radio. Marker/Parking Lights worked.

---Pulled the Headlight Switch and the resistor was showing no continuity whatsoever, so I swapped the switch for another new... and the darned dash lights wouldn't come on unless the knob was thrown to the "dome" position (which we don't have) with the headlight switch on (no fog lights). The new switch apparently burned out as well, cause again, the dash lights aren't working... I am wondering if there is an issue with a notorious Ford "main bod ground" which I have seen on the passenger side frame rail of Rangers (just behind the cross member) as being nothing more than a metal clip with a wire soldered to it. Kind of like a flag terminal. This sort of half-arsed ground has left many Ranger owners on the side of the road because the entire system just shut down.

---Is there a main body ground for the electrical system, that the cooling fan, dash lights and possibly ignition would tie into? If so, where would it be found? My workstation is down due to the PSU cooling fan burning up, so I can't access my Mitchell1 On Demand software :crying:

---What would cause both the #2 & #5 wires to burn up on that relay harness?

---I've attached an image I picked up from IIRC the allmustangs website while researching hundreds of search results from Lougle to find answers... and possible fixes. While the relay suggestion there doesn't seem to be wired in correctly (looks like the switch is energizing the coil, which is completely backward from even german engineering & against correct wiring of a [-] ground German switch that is illustrated for [+] ground), it is a partial solution. Partial as in... why is the remaining portion of the crappy OEM relay even in the vehicle still. I'd chuck it if I had assess... to diagrams!

---Anyone have a full diagram, preferably from Mitchell? While I understand the FSMs are always the best source, I like the full diagrams mitchell produced over the Schemat-agrams that are a mix of both schematics & diagrams. Having a drafting/design certification under my belt, I find it extremely irritating to try and follow... basically, something that is drawn wrong... but mainly I want to look at the whole picture, not "part of the system is on page 428 and the other third is on 572 and... where is the one wire that isn't shown in the other two?"

---BTDT. I have both Mitchell Domestic/Import Classic as well as my International FSMs and I follow everything from the FSMs but* the subdivided wiring diagrams. When my workstation's PSU comes back from repair, I will UL to my album, the Mitchell diagram for the 88 Mustang 2.3L... if it is a one-to-three page full diagram* like I am use to working with. Some have changed in their books as well... hopefully not in this case.

 

[AKA3Toes]

... What would cause both the #2 & #5 wires to burn up on that relay harness?...

---The fan.

---Having removed the fan so I could clean it up with some electric motor cleaner, I spun it by hand and found it to be extremely noisy... like rust was throughout it. Even though the fan previosuly tested good, I hooked it up to a battery I'm charging, using old, 14-2, aluminum household wire (scrap from when I gutted the old house's wiring) and the wire got hot enough that I would say even a mediocre set of jumper cables would have heated up. So the old fan was shot. Move on to a Ford Taurus fan I have, which I was considering mounting on one of my Scout IIs...

... So anyway, I had 1 7-blade cooling fan from IIRC a '90 Ford Taurus that I used the motor and fan from, keeping the Mustang shroud. I don't like toying with the Mustang radiator, so that sounded better to me than mounting the Taurus fan to the radiator.

1. I removed the motor and pigtail from the Taurus & after sizing it up, saw I had to make a couple alterations. The Taurus fan had a ring around it, joining the fan blades which made it too wide in diameter to fit the Mustang shroud
2. I cut the ring off the Taurus fan blade. Then it fit the Mustang shroud perfectly... 0.40" between fan blade & shroud. If I had a helper, he/she could have held the fan while I sawed with a piece of string or a cable saw, but I was alone so I used a hack saw after cutting sections between the fan blades out, with a pair of tin snips
3. I then removed the motor from the stock shroud and cut a 1.5" section out of the mounting bracket (a notch for the weatherproof plug receptacle on the fan motor)
4. The new motor set just cleared the center of the mounting studs on the shroud, so no drilling required, The washers on the nuts would just act as clamps
5. I then shimmed the studs 1/4" with washers (so the studs would clear the blade)
6. Then I bolted the fan down loosely, flipped the shroud over and centered the fan, then snugged the nuts down
7. A couple butt splices, electrical tape & heat shrink and it was ready to bolt in
8. Four bolts later, it was done
9. Twelve hours more & I'll be visiting the AutoZone counter-monkeys to pick up the repair connector/pigtail... well, maybe.

---It's pretty bad when you go to the parts house and have to carry a list of part numbers with you. The reason they gave me for my ordered repair connector/pigtail being cancelled, was that they didn't carry the part anymore. The fact is, the idiot accidentally ordered a Santech Relay/Installation Kit along with the cooling fan/Air Condition relay and they decided to send a Santech cooling fan pigtail. He even showed me the image of they cancelled. NOT THE RIGHT ONE! He even said he was looking at the image and it matched the relay. LMAO! When I gave them the GP Sorenson number, he said they had that so he ordered it... we'll see if they cancel it.

---A full diagram sure would be nice. Anyone? I'd like to trace wires and maybe just hook up two Bosch 30A/40A 12v ISO relays, take this Atari cartridge back to the counter-monkey and refuse the pigtail, then I won't have to worry about struggling to get these parts. Lifetime warranty or not, I'd much rather have Bosch relays installed. They'd be less bulky at least & they can be acquired from 24-hour Wally*Worlds or KMarts.

 

[AKA3Toes]

---K, new Connector/Pigtail installed, #2 & #5 wires spliced w/#5 having a 30A AT Circuit Breaker installed in-line. If it happens again, the idea is the wire will heat up, heating the thermostatic spring in the relay and tripping it. Then when the spring cools down once again, contact will be made, triggering the fan if need be. Told the wife that if the temp needle reaches anything past mid-way, the fan isn't working so shorten her trip home.

---The cooling Fan still sits idle turning when I turn the A/C on. I had thought it would trip the Cooling fan relay doing this... I'd think there would be a sensible reason why they're in the same module, wired together with resistors... Shouldn't the Cooling fan switch on when you turn the A/C on?

 

[Delray Dude]

cooling fan should come on when a/c engaged. Sounds like the relay for the a/c is not working..

You did way too much work!!!


I got the Lincoln Mark VIII fan that covers the entire radiator, ran a 40 amp relay to a fused lead off the battery and used the original positive fan lead to trip the relay. that way there isn't a major amperage going through the cooling system relay box....

Did the same for the 88 because the original module is under the dash and fried due to a meltdown. Got a "new" replacement harness pigtail that a 5.0 doesn't use and found a good module in the yard. spliced in the new harness and did the same fan mod on the 88 and have no problems with the cooling. car barely gets over 180 in the summer heat with a/c on.

 

[Delray Dude]

re-read your post and wanted to add some comments.


your module under the dash is probably partially fried. all the voltage to the fan goes through that module and the original fan with the resistence it had fried the wires. Very bad design if you ask me.... same thing happened on my 88 vert.

I couldn't get the a/c compressor to kick in and it was throwing me for a loop...as i though it was like all others wire to compressor through the pressure swith and then to magnet on compressor. got voltage there and nothing at the clutch. then researched that it goes back to that module under the dash and trips the relay for the cooling fan and then goes to the a/c clutch. So, with the module being fried and the wiring harnes a mess at the module, cut it out and replaced it. next time go to a yard and find any 87, 88 or 89 5.0 and look under the dash - a vigin harness for the control module is taped up and not used - as the 5.0 had a mechanical fan.

Once I spliced in the new harness and rid myself of the bad burnt wires and got a control module out of another 2.3 that looked good, plugged it in and the a/c kicked on.

You really should bypass all the major load to the fan out of the module - and use the original wire to trip a relay under the hood. This way if the fan puts a major load on the wiring - you don't fry the module and under dash harness again.

I suspect that the one relay got cooked and fails to energize the fan when the a/c kicks turns on. Does your compressor engage?