With Regina systems (and as well the early LH systems) where there is a thermal switch inserted in the upper right corner (passenger side) of the rad, about the only way the electric fan can operate continuously when the ignition is on is when the thermal switch on the rad is stuck closed -so your diagnosis and remedy is likely spot on.

If it happened to also run continuously after the ignition is off then both the relay and sensor would have to be gone and both stuck closed, so not a common situation.

For later 900 LH systems where there is no thermal switch in the rad, the story is more complicated where the ECU and an A/C pressostat are both able to control fan operation through the relay. Continuous running in that situation would most likely be a stuck relay -see the FAQ for more detailed diagnosis.

For the early 700s the relays are in the relay tray (front row, leftmost socket). In the later 700s they may be found tied under the right (passenger) side strut tower brace. In the 900s they're up by the right front headlight, as you note.
--
Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now