carrera 3.2 blower relay - testing?

[larrym]

UPDATE - solved

since i live 2 hrs from any nearby guy with a same carrera & further don't know anybody who would let me plug my relay into his car ..........

- spent an hour tracing thru the diagrams & pins-end-to-end with ohmmeter

- figured out how it works

- summary: bench testing involves activating the internal primary ign-on coil/relay & then using 9v battery test sets to check each other relay/coil output while the ign-on or ign-start is active

i can provide my notes to others with the "problem" - there is also a thread showing the internals of the relay & another guy's attempted fix - google it

i have a relay 911.618.153.00 (unknown functionality) from an '89, along with the blower (tested good), extracted from a wreck along with the engine i'm using in my header equipped 914-6;

i have printed the diagrams from PET; the multi feeds & interconnects are puzzling to say the least without knowing which circuits override or are dependent on which others in actual operation

just want to know if the relay is OK so i can sell it, since i'm not needing the blower

this question is inspired by recent wtb post
WTB: Blower Motor Relay for 3.2

[86 911 Targa]

Originally Posted by larrym

how does one bench test this relay to see if it's any good?

i have a relay 911.618.153.00 (unknown functionality) from an '89, along with the blower (tested good), extracted from a wreck along with the engine i'm using in my header equipped 914-6;

i have printed the diagrams from PET; the multi feeds & interconnects are puzzling to say the least without knowing which circuits override or are dependent on which others in actual operation

just want to know if the relay is OK so i can sell it, since i'm not needing the blower

this question is inspired by recent wtb post
WTB: Blower Motor Relay for 3.2

Plug the relay into another car.

[steely]

I haven't seen anything but don't take my word for it.

I think you'll have to plug it in and see if everything autoheat related works. (and now I see Gerry's post)

It's really more of a controller with a dip chip, some discretes, a reed switch and 2 relays.
I did a quick look and only found posts related to footwell blower issues that implicated this controller, along with a work-around.

But I didn't see a full-up write-up on bench testing.

One could open it up, check for burn marks, and test the relays and reed switch maybe, but I don't see a board schematic other than an overall functional block diagram needed to go full comprehensive on it.
There's 12 pins at the interface, so you'd have to check most of them simultaneously, as well as furnish a tach signal (!?) according to the car schematic.

These aren't cheap so I agree its worth something if operational.

[echecsqueen]

[QUOTE=larrym;9592278]UPDATE - solved

I have my relay out and am wondering if you can tell me how to test it. My blower motor works when I supply 12v to it. I prefer not to buy a new relay if it is not the problem.....

this is a 3.2 carrera heat blower relay

911 618 153 00

Is there a way for me to check it ?
thanks

[Jack Stands]

These schematics may help. Energizing the relays and checking continuity may help, though I had heard that bypassing the reed switch is a workaround as that's a known failure point in the controller.

[Jack Stands]

[aj88cab]

Originally Posted by Jack Stands

These schematics may help. Energizing the relays and checking continuity may help, though I had heard that bypassing the reed switch is a workaround as that's a known failure point in the controller.

For future visitors to this thread...That diagram is not entirely correct, and that method of jumper will result in the foot-well blowers running all the time when the engine is running or the ignition is just in the ON/RUN positions. This happens when the red levers are OFF/down (manual heat) or the dial is set to OFF for auto-heat systems.

This is a corrected diagram that includes a jumper configuration that will not have the FW blowers run all the time. The note about the "engine blower removed or disconnected" is optional. The jumper works to run the FW blowers with or without an engine blower installed. If you keep the engine blower in the system, the reed switch feed should be cut as indicated.



As the OP indicated you can check the individual relays with a 9v battery. But the only way to really check the reed switch operation is with a motor connected which is best done in a car. The reed switch needs current in the coil around it to operate, and that current comes from an operating engine blower motor.

As for checking the IC chip on the circuit board...sorry, I got nothing

[echecsqueen]

Thank you guys...it is the relay. Specifically the engine compartment blower coil. Thanks so much!