P1641 and P1642 Codes Thrown

**2kporter** · 08-15-2007, 02:56 PM

I just finished this past weekend installing a manual coolant fan switch in my 96 TransAm. It just taps into the GM 10 pin connector on top of the shock tower (passenger side).
I'm tapping into the blue (H) and green (J) wires to send power to the fan relay. Everything worked great after i installed it and tested it.
Today i decided to drive my TA to work and while i was in Traffic, i kicked on my switch to cool the engine down. WAM SES light came on.

The P1641 and P1642 are fan relay control circuit codes.

Has anyone installed a fan override switch and got these codes? Does anyone have an idea on what the heck caused them? My thoughts was if the fan relay was already on in low mode, maybe i turned on the high mode manually and did something to it.

**5.0THIS** · 08-15-2007, 06:56 PM

I have the SLP switch and have no such problems.

**2kporter** · 08-16-2007, 08:55 AM

Yeah this wasn't the SLP switch i installed. It was a home grown version. I'm thinking about removing it and just going with the SLP version.

Anyone know where to buy one cheap?