|Thanks for that Marc. The problem hasn't occured with mine yet, but you |
never know :)
On an almost side note, remember people about dry solder joints on the
heater control unit itself. This causes no heater function, only cold air.
All you need to do is touch a soldering iron to each contact on the back of
the control unit so melt and re-attach the solder.
>From: Marc Archbold <firstname.lastname@example.org>
>Reply-To: "Supra Club of NZ Mailing List" <email@example.com>
>To: "Supra Club of NZ Mailing List" <firstname.lastname@example.org>
>Subject: [sconz] 89+ A70 Auto Heater and JZA70 ECU fix
>Date: Fri, 09 Mar 2007 10:04:10 +1300 (NZDT)
>Hi all, sharing a couple of fixes that might help someone out in the
>The first is A70 89-93 Heater Blower operation where auto/climate control
>heater blower appeared to be fixed on low, instead of throttling depending
>heating/cooling based on the position of the Temperature control knob.
>- i.e. Blower Switch set to AUTO, Vent set to AUTO.
>Note: The 89+ US TSRM Heater/Aircon is quite different to JDM versions.
>After checking the power, Blower Resistor, Blower Speed control Switch
>on bottom center of heater, linked to the Air mix Cam), the fault was
>to the Blower Control Relay: Mounted in a rubber sleeve Part#88630-24050
>(Equiv Part# 90987-02004) , located on the drivers side rear of the center
>console facing outward toward the door.
>Typical exorbitant Toyota NZ price $97. Aftermarket price $12, from Auto
>Second Fault - JZA70 ECU Erratic operation.
>I have seen two JZA70 ECU's and know of at least two others where the
>will stuble when warm, not start, run erratically when warm and appear to
>intermittent and random in fault.
>The fault is caused by leaky electrolytic Capacitors:
>from memory there are four electrolytic capacitors that require replacing,
>three on the I/O board (Bottom board) one on the CPU board, with the main
>culprit being one in the Injector circuit that leaks onto the circuit
>In two cases, the cap in the injector drive circuit leaks and rots out one
>Hope this helps someone.
>Supra Club of New Zealand - http://www.supras.org.nz/
>Website sponsored by Alltech Diesel & Turbocharger http://www.turbo.co.nz
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