1990 Ford Bronco Horn & Cigar Lighter Troubleshooting Hints - EVTM Page 44-3
Reference · 1987-1991 BroncoAll 95 service procedures
Horn/cigar lighter diagnostic troubleshooting chart: conditions, causes and test actions including checking Fuse 16, Horn Relay connector 460 (Y/LB), and circuit 1 (DB) ground.
Part of 1987-1991 Ford Bronco Service Procedures
This document is page 44-3 of a Ford electrical and vacuum troubleshooting manual (EVTM) covering the Horn and Cigar Lighter circuits, uploaded as applicable to a 1990 Ford Bronco. It presents a 'Troubleshooting Hints' table with three columns: Condition, Possible Cause, and Action. Three conditions are addressed: (1) Horn doesn't work, caused by no voltage at the Horn Relay, with actions including checking Fuse 16, testing the horn switch by metering across the Fuse 16 position, jumpering battery power directly to each horn and grounding the horn bracket, adjusting the horn screw 1/4 to 3/8 turn, checking voltage at the Horn Relay connector 460 (Y/LB) wire, and grounding the Horn Relay 1 (DB) wire; (2) Horn doesn't turn off, caused by a short in circuit, diagnosed by disconnecting connector C219 from the Horn Switch, checking the 1 (DB) wire for shorts to ground, and checking for a short between the 151 (LB/BK) and 1 (DB) wires; (3) Cigar Lighter doesn't work, caused by no voltage at the lighter, diagnosed by checking Fuse 16, voltage at the 460 (Y/LB) circuit, and continuity to ground at the lighter shell. Circuit numbers and wire colors 460 (Y/LB), 1 (DB), and 151 (LB/BK) are referenced throughout.
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Frequently asked questions
- What fuse controls the horn and cigar lighter on a 1990 Bronco?
- Fuse 16: the document instructs checking Fuse 16 for both a horn that doesn't work and a cigar lighter that doesn't work.
- How do I test the horn switch according to this document?
- Remove Fuse 16 and connect a meter across the Fuse 16 position. If the meter reads battery voltage when the Horn Switch is pushed, the switch is good.
- What should I do if the horn won't turn off?
- Disconnect connector C219 from the Horn Switch. If the horn shuts off, replace the Speed Control Switch Assembly. If it continues, check the 1 (DB) wire for a short to ground; if ground is OK, replace the Horn Relay. Without speed control, remove fuse 16 and do a continuity check of the Horn Switch (not depressed); if continuity is present, replace the Horn Switch, otherwise check for a short between the 151 (LB/BK) and 1 (DB) wires.
- What wire color feeds the horn relay and cigar lighter?
- Circuit 460, a Yellow/Light Blue (Y/LB) wire, carries voltage to both the Horn Relay connector and the Cigar Lighter.
- How can I test a horn that doesn't sound at all?
- Attach a jumper between the Battery and the Horn connector and another jumper between the Horn bracket and ground (do this for both left and right horns). If the horn doesn't sound, turn the adjusting screw 1/4 to 3/8 turn and secure; if it still doesn't sound, replace the Horn.
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