Bobcat H4502 (45-02) Fault Code: Right Blinker Error On
Also shown on the panel as 45-02
Right Blinker Error On · ai-assisted, editor-reviewed · Last updated 2026-07-13
TL;DR
H4502 (panel display 45-02) sets when the Bobcat auxiliary controller sees voltage on signal wire 6520, the right blinker relay circuit, when the right blinker switch has not been activated. It points to a wiring short, a stuck relay, or a controller/connector problem on the right turn signal circuit.
Low severity. This code affects the right turn signal function only. It is not tied to engine, hydraulic, or lifting systems, but a non-working or stuck-on blinker is a road safety and DOT compliance issue on machines driven on public roads, so it should be fixed before the machine is used in traffic.
What does Bobcat error code H4502 mean?
H4502 is set by the auxiliary controller when it detects voltage present on signal wire 6520, the wire that carries the command for the right blinker relay, at a time when that command was not actually sent. In other words, the controller sees the right blinker circuit acting like it's turned on when nobody pressed the right blinker switch on the right grip.
Normally, pressing the right blinker switch sends a signal to the auxiliary controller, which then energizes the right blinker relay to flash the right turn signal lamps. When the controller detects voltage on that signal wire without seeing the switch command, it flags H4502 because something downstream, in the wiring, relay, or controller itself, is feeding voltage onto that circuit unexpectedly.
This is an electrical fault confined to the turn signal system. It does not affect drive, lift, or engine functions, but it can leave the operator without a working right turn signal or with one that behaves erratically, which matters for road use and job site signaling.
Common causes of H4502
- Signal wire 6520 shorted to supply voltage, feeding voltage onto the circuit even when the switch is not pressed.
- Failed or sticking right blinker relay that is passing voltage through when it shouldn't.
- Fault inside the auxiliary controller itself.
- Moisture, corrosion, or pushed-back pins in the auxiliary controller connectors, the AWS horn/blinker harness, or the mainframe harness.
- Intermittent condition: if the code is not active at the time of testing, the exact cause may not be identifiable right away. Loose connections, corrosion, pushed-back pins, the controller, or the wire harness (or a combination) are all possible contributors.
How to troubleshoot Bobcat H4502: first checks
- With the key switch in run/enter (on), check whether the code is currently active or was logged historically; an intermittent fault may not be present during testing.
- Inspect the auxiliary controller connectors, the AWS horn/blinker harness, and the mainframe harness connectors for moisture, corrosion, or pushed-back (backed-out) pins.
- Check wire 6520 for a short to supply voltage by tracing it from the right blinker switch through to the auxiliary controller and relay.
- Test the right blinker relay for proper operation; a relay that is sticking or passing voltage internally can trigger this code.
- Wiggle-test harness connectors and wiring near the right grip switch and along the mainframe while watching for the code to set, since intermittent faults often show up only under vibration or movement.
- If no fault is found and the code was only logged historically, note it as intermittent and recheck connections at the auxiliary controller, harness, and relay for a combination of minor issues.
How the code clears
Once the repair is complete, clear the code by cycling power (turning the key switch off, then back on). No separate clearing step is listed beyond cycling power.
Affected models and serial ranges
H4502 appears in our records across 16 Bobcat models. Match your machine by model and serial number.
| Model | Serial ranges |
|---|---|
| S510 | SN A3NJ11001-99999, SN A3NK11001-99999, SN ATZC11001-99999 |
| S530 | SN A7TV11001-99999, SN ATZD11001-99999 |
| S550 | SN A3NK11001-A3NL99999, SN A3NM11001-99999 |
| S570 | SN A7U711001-799999, SN A7U811001-899999 |
| S590 | SN ANMN11001-99999, SN ANMP11001-99999 |
| S630 | SN A3NT12370-99999, SN A3NU11001-11111, SN A3NU11112-99999 |
| S650 | SN A3NV11001-13098, SN A3NV13099-99999, SN A3NW11001-11248, SN A3NW11249-99999 |
| S750 | SN A3P211001-299999 |
| S770 | SN A39511001-99999, SN A3P411001-99999 |
| T550 | SN A7UJ11001-AJZV12276 |
| T590 | SN ALJU11001-999999, SN B37811001-999999, SN B3Z711001-999999 |
| T630 | SN A7PU11001-11663, SN A7PU11664-99999 |
| T650 | SN A3P012214-099999, SN A3P111242-199999 |
| T750 | SN ANKA11001-A99999 |
| T770 | SN A3P811001-899999, SN A3P911001-999999 |
| T870 | SN A3PG11001-99999, SN A3PH11001-99999 |
Frequently asked questions
What does Bobcat code H4502 mean?
It means the auxiliary controller detected voltage on the right blinker relay signal wire, wire 6520, at a time when the right blinker switch was not commanding it. It's an unexpected-voltage fault on the right turn signal circuit.
Is H4502 the same as panel code 45-02?
Yes. H4502 is the alphanumeric code, and 45-02 is the same fault shown in the older numeric panel display format.
Can I keep driving or working with H4502 active?
The fault is limited to the right blinker circuit and does not affect drive, lift, or engine systems, but you should not operate on public roads with a malfunctioning turn signal. Get it diagnosed and repaired before road use.
What usually causes this code?
The most common causes are signal wire 6520 shorted to supply voltage, a faulty right blinker relay, moisture or corrosion in connectors, or pushed-back pins in the auxiliary controller, AWS horn/blinker harness, or mainframe harness connectors. Less commonly, the auxiliary controller itself may be at fault.
The code isn't showing up anymore, does that mean it's fixed?
Not necessarily. If the code is intermittent, it may not be present during testing even though the underlying issue, like a loose connection or corrosion, is still there. Inspect connectors and wiring even if the code isn't currently active.
How do I clear H4502 after making a repair?
Cycle power to the machine by turning the key switch off and back on. No other clearing procedure is listed for this code.
Which Bobcat machines can show this code?
H4502 applies across a range of Bobcat skid-steer and track loader models, including the S510, S530, S550, S570, S590, S630, S650, S750, S770, T550, T590, T630, T650, T750, and T770, T870.