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-   -   Lost turn signal and hazard lights function – Failed CPU No. 2? (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/lost-turn-signal-hazard-lights-function-%96-failed-cpu-no-2-a-1102592/)

jza80 07-06-16 11:39 AM

Lost turn signal and hazard lights function – Failed CPU No. 2?
 
So yesterday I was driving my FD, and part way through the drive I lost turn signal function – when operating the turn signals there is nothing, no lights or clicking. Same with the hazards, nothing. Literally one minute they were working, and at the next intersection they were not. I checked the fuse for this circuit, and it is fine.

In looking at the schematic, it looks like the hazards and turn signals are controlled by CPU No. 2 – all the T/S and hazard switches do is complete a circuit to CPU No. 2 which then sends the signal to the appropriate lamp. I have read some posts about strange alarm and seat belt light function caused by a failing CPU No. 2, but nothing about nonfunctional turn signals. All the other CPU No. 2 functions seem to be working okay AFAIK, although the key-in ignition open-door chime has always activated for both the driver’s side and passenger side doors which is not correct – but I just ignored it. I previously modded my CPU No. 2 with a resistor per the forum write up so that it would flash correctly with LED lamps, in case this is relevant.

Are nonfunctional turn signals/flashers (with working seat belt light functions, etc.) likely the result of a failed CPU No. 2? Thought I’d ask before I ordered a new part. Thanks for any help with this!

OG BBF 07-06-16 12:14 PM


Originally Posted by jza80 (Post 12082632)
So yesterday I was driving my FD, and part way through the drive I lost turn signal function – when operating the turn signals there is nothing, no lights or clicking. Same with the hazards, nothing. Literally one minute they were working, and at the next intersection they were not. I checked the fuse for this circuit, and it is fine.

In looking at the schematic, it looks like the hazards and turn signals are controlled by CPU No. 2 – all the T/S and hazard switches do is complete a circuit to CPU No. 2 which then sends the signal to the appropriate lamp. I have read some posts about strange alarm and seat belt light function caused by a failing CPU No. 2, but nothing about nonfunctional turn signals. All the other CPU No. 2 functions seem to be working okay AFAIK, although the key-in ignition open-door chime has always activated for both the driver’s side and passenger side doors which is not correct – but I just ignored it. I previously modded my CPU No. 2 with a resistor per the forum write up so that it would flash correctly with LED lamps, in case this is relevant.

Are nonfunctional turn signals/flashers (with working seat belt light functions, etc.) likely the result of a failed CPU No. 2? Thought I’d ask before I ordered a new part. Thanks for any help with this!

Most likely the flasher unit. It's a common issue that the solder joints fail inside which cause loss of turn signal and hazard lights. Happened to me. Opened it up and re soldered the dry joint and was good as new. (Could be the same thing as cpu no2, but I've always known it as flasher box/unit. On a RHD it's located under the drivers side dash literally in front and above the fusebox. It's a black box, sort of rectangular, mine had FD01 printed in white on it.

jza80 07-06-16 04:30 PM

Yep that's the one. I believe the part number is FD01-67-560B. Thanks for the info.


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