I just had a little trouble with this code and figured I would post my cause and solution up for anyone else....
It started when I tried to run the air for the first time this season, I had the 1652 code which for a 98 says fan 2 relay something or another but for other years I think the newer years it says its got something to do with chassis pitch output. Anyways the car had an aftermarket trans cooler when I bought it and they used the pins you push through the radiator to hold it in place. I swapped that one out for a bigger better cooler and I guess I missed one of those pins which backed out and held the fan from starting which in turn burned the fan up. I replaced the fan and it worked on low speed just fine but would never go into high speed even with air on. I checked all fuses, relays, grounds, wiring to the fans, connectors, everything was good. I couldn't find much if any info on the web relating to the code or a solution. Luckily I have a nice handheld actron scanner and it has a solutions section called code connect and it said the ignition switch was the most common fix. So with nowhere else to go I replaced it and viola working just fine and no code... I would still suggest checking all the relays/wires and junk first just cause its free.
