1HD-FT AC — no idle-up after compressor replacement

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Joined
Feb 14, 2026
Threads
3
Messages
3
Location
UK
80 series, 1HD-FT, RHD.


Compressor seized solid. Internal failure, not the clutch — debris through the system. Full replacement done: compressor, condenser, expansion valve, drier, flush, oil to spec, new o-rings.
Cooling correct, vacuum held.
One problem. Idle drops when the compressor engages. No idle-up at all.

Assuming the idle-up actuator line at the injection pump wasn't reconnected. Anyone confirm the routing on the 1HD-FT — which line feeds it and where it terminates at the pump?

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Is the vaccuum solenoid getting energized ? If not, it is a very long electro-mechanical circuit for the diagnostic in the FSM.
Here are some things to check:
-(10a Gauge Fuse)
-AC starter cut relay
-AC magnetic clutch relay
-AC Cut Relay (Water Temp)
-AC Water Temps Switch
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