[BroncoBud]

So my radio is not keeping memory and my cigarette lighter is not working. I checked the fuse's and they are fine so I checked the for power and the fuse's are getting power.

I am unable to pull the fuse box completely out to see what the wires are but crawling underneath it looks to be a light blue wire with a white stripe.
I do not know where to go from here.

 

[jermil01]

Hey @BroncoBud , I'm not sure where the grounds are for those, but I'd suggest checking all of you battery grounds for signs of corrosion and clean or replace as necessary.

 

[BroncoBud]

I placed the fuses back because I noticed the ground plug at the cigarette lighter was not connected for some reason. Once I connected the ground the lighter began to work. Though the radios "always hot" wire (light green/purple) is not hot at all.

 

[sackman9975]

Those aren't grounds in the fuse box. Those are line and load sides.

 

[BroncoBud]

Yea, I figured they were something other than what I thought they were, my logic always fails me like that. So I replaced the fuses and am trying to figure out how best to diagnose the situation of my radio not having power from the always hot line.

 

[wood4d]

You can test those fuses by just reading off the metal tabs on the fuse

 

[miesk5]

Yo Bud,
Do you have the OEM Base, or cassette or Compact Disc Radio?:
STATION RECALL MEMORY TEST

• Press SEEK or TUNE buttons to a desired station.
• Press and hold one of the (1 through 5) memory buttons for two seconds until station sound is returned (repeat for all five buttons).
• Do for AM, FM1 and FM2 bands using 15 stations.
• Turn radio chassis off, then on.
• Press each station recall button and verify memory storage.

Is memory test successful?

Yes	No
GO to A9.	REMOVE radio chassis for service.

A9 VOLUME CONTROL TEST

• Press VOLUME (+) and (-) to verify an increase and decrease in volume sound from radio chassis.

Does volume change properly?

Yes	No
GO to A10.	CHECK radio speakers and connections. REFER to Symptom Chart if diagnosis finds radio speakers inoperative. REPEAT volume test. If volume still inoperative, REMOVE radio chassis for service.

A10 TUNE CONTROL TEST (ESR)

• Press TUNE button (>) or (<) to change the frequency station up or down one increment at a time. Change frequencies quickly by holding the (>) or (<) side of button. Verify for all bands.

Does TUNE operate properly?

Yes	No
GO to A11.	REMOVE radio chassis for service.

A11 TUNE ANTENNA TEST (OPTIONAL)

• Tune radio on AM band outside of building.
• Press SEEK to observe all listenable stations on band. Count number that can be tuned.
• Compare to a vehicle with known good radio chassis.

Are normal number of stations received?

Yes	No
GO to A12.	If an absolute number of stations cannot be tuned, PERFORM radio antenna component test. REFER to Components Tests in this section. If antenna operative, REMOVE radio chassis for service.

A12 CLOCK — CONTROL TEST

• Press CLOCK button and simultaneously press SEEK (>) to advance hours or SEEK (<) to advance minutes. Release CLOCK button.

Does CLOCK operate properly?

Yes	No
GO to A13.	REMOVE radio chassis for service.

A13 TONE CONTROL TEST

• BASS: Press AUDIO button repeatedly until BASS is displayed. Press VOLUME (+) to increase low frequency sounds and VOLUME (-) to decrease low frequency sounds.
• TREBLE: Press AUDIO button repeatedly until TREB is displayed. Press VOLUME (+) to increase high frequency sounds and VOLUME (-) to decrease high frequency sounds.
• Verify proper display and sounds for each tone control.

Do BASS and TREBLE operate properly?

Yes	No
GO to A14.	CHECK radio speakers and connections. REFER to Symptom Chart if diagnosis finds radio speakers inoperative. If BASS and/or TREBLE still inoperative, REMOVE radio chassis for service.

A14 BALANCE CONTROL TEST

• BALANCE: Press AUDIO button repeatedly until BAL is displayed. Press VOLUME (+) to shift sound to right radio speakers and VOLUME (-) to shift sound to left radio speakers.
• Verify proper display and sound in proper radio speakers.

Does BALANCE operate properly?

Yes	No
GO to A15.	CHECK radio speakers and connections. REFER to Symptom Chart if diagnosis finds radio speakers inoperative. If BALANCE still inoperative, REMOVE radio chassis for service.

A15 FADER CONTROL TEST

• FADER: Press AUDIO button repeatedly until FADE is displayed. Press VOLUME (+) to shift sound to rear radio speakers and VOLUME (-) to shift sound to front radio speakers.

Does FADER operate properly?

Yes	No
REFER to symptom chart to determine if an inoperative condition exists.	CHECK radio speakers and connections. REFER to Symptom Chart if diagnosis finds radio speakers inoperative. If FADER still inoperative, REMOVE radio chassis for service.

A16 CHECK INOPERATIVE OR INTERMITTENT

• Verify if condition is intermittent or inoperative.

Is condition intermittent?

Yes	No
GO to A19.	GO to A17.

A17 CHECK FUSE

• Key off.
• Check fuse 11 (15A) in instrument panel fuse panel.
• Check fuse 17 (50A) in power distribution box.

Are fuses open?

Yes	No
REMOVE open fuse and GO to A18.	GO to A19.

A18 CHECK FOR GROUNDED POWER FEED

• Key off, check Circuit 137 (Y/BK) at radio chassis connector C1 for a short to ground.

Is power feed grounded?

Yes	No
LOCATE short to ground and REPLACE or SERVICE. REPLACE fuse(s). RETEST system.	REPLACE fuse and RETEST system. If fuse still opens, REMOVE radio chassis for service.

A19 CHECK POWER FEED

• Connect digital volt-ohmmeter between radio chassis connector C1 Circuit 137 (Y/BK) and known good ground.
• Key to RUN or ACCESSORY.

Does digital volt-ohmmeter indicate 10 volts or more?

Yes	No
GO to A23.	GO to A20.

A20 CHECK WIRING CONTINUITY — FUSE TO RADIO

• Remove fuse 17 (50A) temporarily.
• Check continuity between fuse 17 output cavity and radio chassis connector C1 Circuit 137 (Y/BK).

Is continuity present?

Yes	No
GO to A21.	SERVICE wiring as required. RETEST system.

A21 CHECK WIRING CONTINUITY — FUSE TO IGNITION SWITCH

• Check continuity between fuse 11 (15A) input cavity and ignition switch Circuit 297 (BK/LG).

Is continuity present?

Yes	No
RECONNECT fuse and GO to A22.	SERVICE wiring as required. RETEST system.

A22 CHECK IGNITION SWITCH POWER

• Connect digital volt-ohmmeter between ignition switch connector Circuit 297 (BK/LG).
• Key to RUN or ACCESSORY.

Does digital volt-ohmmeter indicate 10 volts or more?

Yes	No
REMOVE radio chassis for service.	SERVICE ignition switch, fuse P (50A), or Circuit 37 (Y) for open. REFER to Section 14-00.

A23 CHECK RADIO SPEAKERS

• With radio chassis operating, check if condition is on all radio speakers.

Is condition present on all radio speakers?

Yes	No
GO to A24.	GO to A25.

A24 CHECK RADIO ANTENNA

• Check radio antenna, cable connections and wiring.

Is antenna system operating properly?

Yes	No
GO to A25.	CONNECT, SERVICE or REPLACE antenna components as required. RETEST system.

A25 CHECK RADIO CHASSIS

• Substitute known good radio speakers to radio chassis.
• Verify if condition is in radio speaker or radio chassis operation.

Is radio chassis operating?

Yes	No
CONNECT, SERVICE or REPLACE radio speakers and wiring as required. RETEST system.	REMOVE radio chassis for service.

PINPOINT TEST B: RADIO CHASSIS DISPLAY BLANK — RADIO CHASSIS OPERATES
B1 CHECK OPERATION OF RADIO CHASSIS

• Key to RUN or ACCESSORY.
• Press radio POWER on.

Isradio chassis display lit?

Yes	No
GO to A1.	GO to B2.

B2 CHECK QUALITY SOUND FROM RADIO SPEAKERS

• Verify that quality sound is coming from radio speakers.

Is quality sound coming from radio speakers?

Yes	No
DISCONNECT fuse 11 (15A) and GO to B3.	GO to A1.

B3 CHECK WIRING CONNECTIONS

• Check wiring connectors and wires for damage, corrosion or open wire at radio chassis connector C1 Pin 6, Circuit 137 (Y/BK).

Are wires and connections OK?

Yes	No
RECONNECT fuse and GO to B4.	SERVICE harness, connector and wiring as required. RETEST system.

 

[BroncoBud]

The PO installed some 20 dollar aftermarket radio. When the key is on everything works fine, speakers, display, channels, everything is fine. But, when I turn the key off any settings for saved stations, or audio preferences are not saved because "always hot" light green/purple wire is not getting but 0.03v. The both fuses are good and getting power. I am currently tracing the wire from the radio harness to wherever it may lead under the dash. #downtherabbithole
This diagram shows the LTGRN/PPL wire going to a fuse box in the engine compartment on the left side... Left side meaning when I am in the cap looking out or when I am under the hood looking at the engine. Because there is only one on the driver side in the engine compartment that I am going to assume is it. Unless there is some super secret one on the passenger side. The 20A fuse is intact and there is 12v going into it.

 

[rla2005]

The underhood power distribution/relay box is on the driver side (left). Fuse 1 provides power for that circuit.

 

[BroncoBud]

From this point. (After fuse is reinstalled)

To this point.

It is losing power.
Is there maybe a fusible link or firewall plug connection between these two points? I had a issue where a fusible link corroded inside the wire harness and I had to pull the whole thing out to find and repair it for the inline fuel pump on my truck.

 

[rla2005]

Power for the radio KAM goes through C202 Pin 71 (Light Green/Purple), the big connector on the firewall.

 

[rla2005]

From this point.
View attachment 173109
To this point.
View attachment 173110
It is losing power.

If you have power at one side of the fuse as shown in the first photo, power will not be at the light green/purple wire unless you re-install Fuse 1. Power cannot jump across an open fuse slot.

 

[BroncoBud]

So it is getting power to the under hood fuse box but before it gets to the giant plug on the firewall it loses power. I tested from the inside firewall plug to the radio and it's a solid connection. So there is a break somewhere between under the engine bay fuse box to the engine bay firewall plug. I am not going to take the whole box out and cut open the wire harness, everything else is getting power and working correctly, so I ran a hot wire with a 20amp fuse to the radio, and removed the fuse from the bad connection in the box. This trucks so old that if I go messing with all that for 1 wire clips, plugs, and who knows what else will just start falling apart.

[Under hood fuse box]-x--------x-[Under hood firewall plug]
[Inside firewall plug]-------[Radio]