To extend my comment, these switches don't have any pollable environment sensors. Only WS-C3524-PWR-XL-EN model has pollable fan sensor.

They've been completely out of support since 2007 and you'll never get newer software than WC17 which you are running.

We are having difficulties finding people who'll accept them free from us, so we usually just trash them. If I'd have XL switches and no budget I'd upgrade them to 3550, which is also EOL, but much superior switch and can be acquired for 50USD/pcs. 3550 runs modern IOS, 12.2(55)SE8 but technically is out of SW maintenance.

With 3550 you'd at least get MST, QinQ, L2PT, SSH, proper storm-control, IP routing, QoS, ACLs, SPAN.

Setting up the configuration synchronization mode (conf sync) involves creating a switch profile (switch-profile). Cisco has a lot of documents regarding this, e.g. Chapter: Configuring Switch Profiles:

Prerequisites for Switch Profiles

Switch profiles have the following prerequisites:

• You must enable CFSoIP distribution over mgmt0 on both switches by entering the cfs ipv4 distribute command.
• You must configure a switch profile with the same name on both peer-switches by entering the config sync and switch-profile
  commands.
• Configure each switch as peer switch by entering the sync-peers destination command

Configuration Guidelines and Limitations

Switch profiles have the following configuration guidelines and limitations:

• You can only enable configuration synchronization using the mgmt0 interface.
• You must configure synchronized peers with the same switch profile name.
• Commands that are qualified for a switch profile configuration are allowed to be configured in the configuration switch profile
  (config-sync-sp) mode.
• Supported switch profile commands relate to vPC commands. FCoE commands are not supported.
• One switch profile session can be in progress at a time. Attempts to start another session will fail.
• Supported command changes made from the configuration terminal mode are blocked when a switch profile session is in progress. You should
  not make unsupported command changes from the configuration terminal
  mode when a switch profile session is in progress..
• When you enter the commit command and a peer switch is reachable, the configuration is applied to both peer switches or neither switch. If there is a commit failure, the commands remain in the switch profile buffer. You can then make necessary corrections and try the commit again.
• Cisco recommends that you enable pre-provisioning for all Gigabit-Ethernet Modules (GEMs) and Cisco Nexus Fabric Extender
  modules whose interface configurations are synchronized using the
  configuration synchronization feature. Follow these guidelines in
  Cisco Nexus Fabric Extender A/A topologies where the Fabric Extenders might not be online on one switch and its configuration is changed
  and synchronized on the other switch. In this scenario, if you do not enable pre-provisioning, a commit fails and the configuration is
  rolled back on both switches.

Configuring Switch Profiles

You can create and configure a switch profile. Enter the switch-profile name command in the configuration synchronization mode (config-sync).

Before You Begin

You must create the switch profile with the same name on each switch and the switches must configure each other as a peer. When connectivity is established between switches with the same active switch profile, the switch profiles are synchronized.

SUMMARY STEPS

1. configuration terminal
2. cfs ipv4 distribute
3. config sync
4. switch-profile name
5. sync-peers destination IP-address
6. show switch-profile name status
7. exit
8. copy running-config startup-config