my new old ford

nathan351

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Oct 3, 2014
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Picked up an 85 bronco that's been sitting in a field for almost a decade. The rats have chewed the wiring harness on the drivers side to the relays on the firewall, so I'm trying to find some wiring diagrams.

I have the 351 and the 4 bbl so does this mean I have eec? This is my first older ford.

 

nathan351

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I'm thinking about buying a 1984 evtm from eBay I think it's the same as an 85.

 
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miesk5

96 Bronco 5.0
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Yo Nathan,

As Seabronc advised; Ford EVTM is best to use.

Here are some Wiring Diagrams & Info;

300 CID, 84-85, Feedback Carbureted Problem Areas; "...This pickup/Bronco application typically suffers from abuse, neglected service and a poorly designed manifold and feedback system. The vehicle will drive tolerably in open loop all the time, suffering from poor driveability and fuel economy (typically in the 8-10 mpg range). Check the mixture control solenoid on the carburetor for a varying duty cycle. A fixed 50 percent duty cycle is the open-loop default value. Check the oxygen sensor for switching (frequency) and amplitude. Verify powers and grounds to the ECU (computer - located inside, above the accelerator pedal). The ECU and 02 sensor grounds are on the firewall in the engine compartment low on the driver's side. Other critical inputs to the computer are the coolant temperature sensor and manifold absolute pressure (MAP) sensor (frequency-based), which both ground ahead and above the battery on the right inner fender well. Manifold leaks are very common (both intake and exhaust). Check all manifold, carburetor mounting and manifold preheat bolts and gaskets for tightness and leaks (flowing propane around gasket areas makes this fairly simple). The exhaust manifold is a relatively thin casting and can be badly warped, particularly if the vehicle has been heavily loaded, used for towing or driven through deep water. A leaking exhaust manifold will dump raw oxygen on the O2 sensor and can make the feedback system attempt to go rich. Carburetor throttle shaft wear is an area for particular attention. Some of the carburetor screws have a propensity for vibrating loose and having the carb literally disassemble itself in normal use. When rebuilding the carburetor pay careful attention to the reassembly of the accelerator pump components -- the washer goes on top of the diaphragm, not below it. This problem has been seen on several remanufactured carburetors as supplied from the rebuilder. Rejetting should be considered a last resort. Air injection switching (upstream, downstream), exhaust system integrity, and catalyst function are areas of common problems on these trucks as well..."

Source: by aircarecolorado.com

=====

Fuse Block Diagram in an 85.gif

Fuse Block Diagram in an 85

========

Neutral Safety Switch (also referred to as Back-Up Switch) Wiring Color Codes in an 85; "...This schematic has a picture of the neutral safety/backup lamp switch in the corner, and gives the wire colors for the back up lamp circuit in the schematic. The neutral safety portion of the connector has a white with pink going in,(if it was equipped with starter interrupt) and a red with light blue going out to the starter relay. Without starter interrupt, both the wires going into and out of the neutral safety switch are red with a lt blue tracer..."

Neutral Safety Switch) Wiring in an 85.gif

============

Also check w/local library; most have Chilton o-line service from Home using library ID & password;

other have All-Data (Best, same as Ford EVTM/PCED or Auto Repair Reference Center (ARRC)

Auto Zone has wiring diagrams in their Vehicle Repair Guides (Free for MyZone Members) - Register there t view, print etc.

Here are some for example;

1985 F-Series pick-up and Bronco, section one.gif

1985 F-Series pick-up and Bronco, section one

1985 F-Series pick-up and Bronco, section two.gif

1985 F-Series pick-up and Bronco, section two

 

miesk5

96 Bronco 5.0
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Oct 18, 2005
Messages
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Yo Nathan,

As Seabronc advised; Ford EVTM is best to use.

Here are some Wiring Diagrams & Info;

300 CID, 84-85, Feedback Carbureted Problem Areas; "...This pickup/Bronco application typically suffers from abuse, neglected service and a poorly designed manifold and feedback system. The vehicle will drive tolerably in open loop all the time, suffering from poor driveability and fuel economy (typically in the 8-10 mpg range). Check the mixture control solenoid on the carburetor for a varying duty cycle. A fixed 50 percent duty cycle is the open-loop default value. Check the oxygen sensor for switching (frequency) and amplitude. Verify powers and grounds to the ECU (computer - located inside, above the accelerator pedal). The ECU and 02 sensor grounds are on the firewall in the engine compartment low on the driver's side. Other critical inputs to the computer are the coolant temperature sensor and manifold absolute pressure (MAP) sensor (frequency-based), which both ground ahead and above the battery on the right inner fender well. Manifold leaks are very common (both intake and exhaust). Check all manifold, carburetor mounting and manifold preheat bolts and gaskets for tightness and leaks (flowing propane around gasket areas makes this fairly simple). The exhaust manifold is a relatively thin casting and can be badly warped, particularly if the vehicle has been heavily loaded, used for towing or driven through deep water. A leaking exhaust manifold will dump raw oxygen on the O2 sensor and can make the feedback system attempt to go rich. Carburetor throttle shaft wear is an area for particular attention. Some of the carburetor screws have a propensity for vibrating loose and having the carb literally disassemble itself in normal use. When rebuilding the carburetor pay careful attention to the reassembly of the accelerator pump components -- the washer goes on top of the diaphragm, not below it. This problem has been seen on several remanufactured carburetors as supplied from the rebuilder. Re-jetting should be considered a last resort. Air injection switching (upstream, downstream), exhaust system integrity, and catalyst function are areas of common problems on these trucks as well..."

Source: by aircarecolorado.com

=====

View attachment 13643

Fuse Block Diagram in an 85

========

Sample diagram-how to read and interpret wiring.jpg

Sample diagram-how to read and interpret wiring

Common wiring diagram symbols.gif

Common wiring diagram symbols

Neutral Safety Switch (also referred to as Back-Up Switch) Wiring Color Codes in an 85; "...This schematic has a picture of the neutral safety/backup lamp switch in the corner, and gives the wire colors for the back up lamp circuit in the schematic. The neutral safety portion of the connector has a white with pink going in,(if it was equipped with starter interrupt) and a red with light blue going out to the starter relay. Without starter interrupt, both the wires going into and out of the neutral safety switch are red with a lt blue tracer..."

View attachment 13644

Ignition Lock Cylinder Adjustment & Switch Pin-Out Diagram & Continuity Testing (Logic Tables) in an 83; "...The following procedure is from the 1983 Ford Service manual, with a few minor wording changes, but should work for any year. Also included are a couple of illustrations from the same procedure to help you visualize it..."

Source: by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums

http://broncozone.com/topic/7243-ignition-switch-adjustment-proceedure/

Ground Locations in an 84; G203 RH side of engine; G208 near TPS; G209 forward of RH side of dash panel; G701 behind IP near LH side of radio; G757 front of engine near distributor

Source: by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums

============

Also check w/local library; most have Chilton o-line service from Home using library ID & password;

other have All-Data (Best, same as Ford EVTM/PCED or Auto Repair Reference Center (ARRC)

Auto Zone has wiring diagrams in their Vehicle Repair Guides (Free for MyZone Members) - Register there t view, print etc.

Here are some for example;

View attachment 13641

1985 F-Series pick-up and Bronco, section one

View attachment 13642

1985 F-Series pick-up and Bronco, section two

 

miesk5

96 Bronco 5.0
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yo,

Also, in addition;

1985 Ford Bronco Factory Foldout Wiring Diagram

http://www.faxonautoliterature.com/1985-Ford-Bronco-Factory-Foldout-Wiring-Diagram-P24808.aspx

$29.00

This is the original wiring diagram printed by Ford for dealer mechanics. You can follow the wiring in your truck from bumper-to-bumper. It will help you to understand connector configurations, and locate & identify circuits, relays, and grounds. Although the schematic is in black and white, the color of each wire is noted. You will not find this diagram in your shop manual. The schematic measures 11" x 12.5" when folded up, and opens up to 11" by 24.5". Diagrams may be folded in half for shipping. The diagram pictured is an example of this type when unfolded, but is not the actual diagram for your vehicle. Buy now for the best electrical repair info--the factory wiring diagram.

Exact Title:

1985 Truck Wiring Diagrams Bronco

Page Count:

17

Wiring Diagrams?:

Included

Authenticity:

This item is original.

Dimensions:

12.50 x 11.00 x 0.25

OEM Part Number:

365198O85

=================

OR

1985 Ford Full size Bronco Foldout Wiring Diagram Electrical Schematic OEM 85

http://www.ebay.com/itm/1985-Ford-Full-size-Bronco-Foldout-Wiring-Diagram-Electrical-Schematic-OEM-85-/360380032875

US $34.95

New customers get $15 back on 1st purchase

Subject to credit approval.

This is the original wiring diagram printed by Ford for dealer mechanics. You can follow the wiring in your truck from bumper-to-bumper. It will help you to understand connector configurations, and locate & identify circuits, relays, and grounds. Although the schematic is in black and white, the color of each wire is noted. You will not find this diagram in your shop manual. The schematic measures 11" x 12.5" when folded up, and opens up to 11" by 24.5". Diagrams may be folded in half for shipping. The diagram pictured is an example of this type when unfolded, but is not the actual diagram for your vehicle. Buy now for the best electrical repair info--the factory wiring diagram.

Exact Title:

1985 Truck Wiring Diagrams Bronco

Page Count:

17

Wiring Diagrams?:

Included

Authenticity:

This item is original.

Dimensions:

12.50 x 11.00 x 0.25

OEM Part Number:

365198O85

++++

Helm Incorporated is FORD's Publisher & distributes factory authorized technical publications

1985 Engine/Emission Bound Service Manual

Price: $60.00

In Stock - Reproduction of Original Publication

Media: Paper

Language: English

Item/Part #: 36512632685H

Developed by Ford Motor Company, this shop manual provides detailed repair instruction written by the manufacterer. Information contained in each body type specific manual has been developed to aid technicians in diagnosing and repairing vehicle components and systems. Each manual covers the entire vehicle bumper to bumper including specifications, diagnosis and testing, in vehicle repairs, component removal and installation and complete engine and transmission rebuilding.

Description:

Instructions And Procedures For Routine Repair Adjustment Maintenance Work Diagnosis/Testing And Removal/Installation Of Parts For Various Vehicle Systems.

Buy Online or Call (800) 782-4356

© 2014 Helm Incorporated.

 

miesk5

96 Bronco 5.0
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Is the helm manual really worth $60?
yo,

Yes!

But look for it on e bay, Craigs and at times, AMAZON

as Seabronc wrote; 1985 Ford Bronco EVTM

Also, I have this Haynes that is good!

HAYNES red cover Ford PICK-UPS & BRONCO 1980-1996.jpg

Some wiring diagrams are same as posted above. Look at them & compare what you see for compnoents such as starter. relay, etc.

Whatever you buy, ensure it is for Carbed Bronco and not EFI.

========

Ron Francis Harness Review in an 84 Source: by justshootme84, Seabronc & Broncobill78

http://broncozone.com/topic/12864-installing-new-wiring-harness/

 
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nathan351

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Yeah i already made the mistake or getting a Chilton and not knowing the basturds changed the manuals.

 

Seabronc

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Haynes and Chiltons are not my favorite manuals.  They are a Readers Digest of the real thing and leave out information that in their opinion is not relevant.  If you intend to be a serious wrencher on the truck, I recommend the full set of shop manuals which are also available on eBay.

Good luck and welcome to BroncoZone

 

nathan351

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Oct 3, 2014
Messages
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Well I got my evtm but so far it's still no help as to what these two mystery relays are or where they need to go.

 

lynchsg

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My 1982 had an EEC III on it. Gave it a hair cut. Edelbrock 650 4BBL, Edelbrock intake, coated shorty headers, 3" custom exhaust with a Flowmaster "Big" SUV muffler and a MSD, vacuum advance, externally Big Yellow Accel coiled distributor. 14" x 4" K&N air filter. 25 degree advance and it runs like a monster. 270 Comp 302 Cam with minor flow work and 9.5:1 compression. Unfortunately, 10 MPH and won't pass smog. Luckily in Mohave County, AZ we don't have smog certs!

 

nathan351

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My 1982 had an EEC III on it. Gave it a hair cut. Edelbrock 650 4BBL, Edelbrock intake, coated shorty headers, 3" custom exhaust with a Flowmaster "Big" SUV muffler and a MSD, vacuum advance, externally Big Yellow Accel coiled distributor. 14" x 4" K&N air filter. 25 degree advance and it runs like a monster. 270 Comp 302 Cam with minor flow work and 9.5:1 compression. Unfortunately, 10 MPH and won't pass smog. Luckily in Mohave County, AZ we don't have smog certs!
At this point I'm on the fence if I even want to try to revive this thing. I'd almost rather just get a 460 since my current engine will need the a rebuild just like a junkyard motor. 

 

miesk5

96 Bronco 5.0
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yo,

What are the wire colors of the relays?

84-86 351W H.O. Holley 4180 4-bbl carb electric choke relay;

by our Friend JUSTSHOOTME (RIP)

relays are linked to the choke, one1 of them is also linked to the EGR.

horn relay is located on the speed control amplifier

85 horn relay located on the speed control amplifier.gif

Bronco F-150 thru F-350, E-150 thru E-350 and Super F Series

The horn relay is use on vehicles equipped with speed control and is located under the left side of the instrument panel, left of the steering column and is mounted on the outboard attaching screw of the speed control amplifier module

horn relay is located on the speed control amplifier2.gif

 

nathan351

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Oct 3, 2014
Messages
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Well here's some pictures. I've got some wires reconnected and I've got lights but no turn signals. I think the starter relay is shot so I bypassed it to check the starter and the motor does turn over.

20141006_185038.jpg20141006_185931.jpg20141006_185858.jpg20141016_180600.jpg20141016_180250.jpg

20141016_180315.jpg

 
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nathan351

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Oct 3, 2014
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I'm starting to understand why everyone l talks so much shit on fixing fords. Random connectors leading to relays I still can't find in this evtm.

Do I have duraspark or duraspark 2 or some eec variation? What's this with ammeter and without?

 

Seabronc

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Never had a problem fixing a Bronco, then I never had a Rat chew one up.  The color codes and plugs are all listed in the schematics.  I suggest you do one function at a time, ie. alternator hookup, then ignition, etc.  

From what I can see in your pictures, it looks like a duraspark 2.

Ammeter or no ammeter just changes where the charge wires from the alternator go. Do you have an ammeter on the dash.  They suck and usually don't work anyway, so you could just wire as though it didn't have am ammeter and install a volt meter in stead.

Does the truck have a trailer hitch?  If so, those relays are probably for it.  I can't see a broad enough view to tell much about what is there.  

A couple of those other pictures are pretty obvious as to the location of where some of the trashed wires went. 

Good luck,

:)>-

 
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