TSRM/MK2 Supra/Repair Manual
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BE/Body Electrical System — Heater Troubleshooting, page 63

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Heater Troubleshooting — MK2 Supra Body Electrical System, page 63
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Page text (OCR transcript)
BODY ELECTRICAL SYSTEM — Heater                                BE-63

HEATER
Troubleshooting

Problem | Possible cause | Remedy | Page

Blower does not work when fan switch is on | Circuit breaker OFF | Reset breaker and check for short | BE-4
 | Heater main relay faulty | Check relay | BE-63
 | Heater blower switch faulty | Check switch | BE-63
 | Heater blower resistor faulty | Check resistor | BE-64
 | Heater blower motor faulty | Replace motor |
 | Wiring or ground faulty | Repair as necessary |

Incorrect temperature output | Control cables broken or binding | Check cables | BE-64
 | Heater hoses leaking or clogged | Replace hose |
 | Water valve faulty | Replace valve |
 | Air dampers broken | Repair dampers |
 | Air ducts clogged | Repair ducts |
 | Heater radiator leaking or clogged | Replace radiator |
 | Heater control unit faulty | Repair control unit |

Heater Blower Switch

INSPECTION OF HEATER BLOWER SWITCH

INSPECT SWITCH CONTINUITY
Inspect heater blower switch continuity.

Switch position | Terminal 10 | 4 | 9 | 5 | 8 | 6 0* | 7
OFF | | | | | | o—o |
I | o—o | | | | | o—o |
II | o—o | o—o | | | | o—o |
III | o—o | | | o | | o—o |
IV | o—o | | | | o | o—o |
* For illumination light

If continuity is not as specified, replace the switch.

Heater Relay

INSPECTION OF HEATER MAIN RELAY

1. INSPECT RELAY CONTINUITY
(a) Check that there is continuity between terminals 1 and 3.
(b) Check that there is continuity between terminals 2 and 4.
(c) Check that there is no continuity between terminals 4 and 5.
If continuity is not as specified, replace the relay.