* Under the hood, in the fuse box: This is the most likely location. The fuse box is usually located near the battery, often on the passenger side fender well. Look for a relay labeled "cooling fan," "radiator fan," or something similar. The relay itself might be larger than typical relays.
* Under the dash, in the fuse panel: Less common, but possible. This is usually found beneath the steering column, often requiring removing a panel to access it.
* Integrated into the PCM (Powertrain Control Module): While less likely on a '98 DeVille, some later models integrated this function. This wouldn't be a replaceable relay, but rather a component within the PCM itself.
To find it:
1. Consult your owner's manual: This is the best starting point. The manual should have a diagram showing the location of relays and fuses.
2. Check the fuse box under the hood: Carefully examine all the relays. Some may be labeled, others might not. You may need to compare sizes to those known to be in the fuse box or use an automotive relay tester (or even a multimeter to check for voltage).
3. Look for a large, usually 2-pole relay: The cooling fan relay is often larger than standard automotive relays.
4. If you can't find it in the obvious places: A qualified mechanic or an online Cadillac DeVille forum might be able to provide more precise guidance based on the VIN or other specific details of your vehicle. Providing your VIN would assist in confirming specific location.
Remember to turn off the ignition before working with relays or fuses to avoid electrical shock.
