L32 Swap with P1673 Code (Page 1/1) TurboGN APR 17, 04:58 PM I have a 1988 Fiero GT with an L32. I have a code that comes right back after deleting it. OBD Code P1673 Engine Hot Lamp Control Circuit OBD Code P1673 Fan Relay Malfunction – High Speed My SES light is not on, I can hear the fan working, and it's not overheating. phonedawgz APR 17, 08:11 PM There are two fan relay outputs from the PCM. It appears the programmer didn't program out the second (high speed) fan output diagnostics out of your PCM. You could either have the PCM reprogrammed to program out that relay, or add the relay at the PCM but connect the output of the relay to nothing. The coil of the 12v relay should connect to unswitched +12v and the other side of the relay coil should connect to the high speed relay output pin. ------------------ Second problem - Fieros have a TEMP light along with the TEMP gauge. Did your harness maker include a lead for the TEMP light? Any chance it works? You couud check for voltage on the HOT light wire at the pcm. that wire when grounded (key on) should illuminate the light in the dash. If you don't care about the light since you have a gauge anyway, you could also install a dummy light at the PCM and make the trouble go away. TurboGN APR 18, 09:29 AM Thank you for the information, I'll have to check it out today. TurboGN APR 19, 10:19 AM It was programmed to allow the use of a second fan in the future and doesn't affect anything. Thank you for the help.