I've recently started using the A/C in my newly acquired '93 240 -- and in some stop and go traffic the temperature started to climb (which must have been really bad, considering it has that "compensation board" to moderate such fluctuations). Anyway, I got out and noticed that the aux. fan wasn't running.
(BTW, when the traffic started moving, the temp. promptly dropped, so the lack of fan is probably the overheating reason -- I just have to fix the fan).

Since this is my first post-'85 240, I'm not familiar with the locations of all the relays (it's quite different than the pre-'86's I'm used to) -- in fact, I'm not familiar with having such an aux. fan. So, as the first check, can anyone suggest where to start checking relays and such? What device (a relay, a switch on the A/C system, etc.?) is supposed to switch on that fan, and where is it located [the fan's wires gets lost in a wire bundle and I don't know where they exit.]
Thanks, folks.

You can cross-wire (jump) the wiring harness that connects to the high side refrigerant pipe. The place to look is adjacent to the alternator area, and the pipe is attached to the right side frame rail in the engine compartment. There is a little offshoot from the pipe, and a switch mounted on it with a plug going into it. Take the plug off and put a wire in it. then turn the A/C switch on. IN about 5 seconds the fan should turn on.

If that doesn't work, the relay could be cashed. Or the fan itself; they've been known to seize. You can put direct voltage to the fan to see if it'll run. THat is effective.

The relay is clipped to the ignition coil in later models. It's a black relay, four wires going out of it. The same relay used in 700 series models for both radio interference suppression, and fan relays.
--
Chris Herbst, near Chicago.

Chris,
My aux elect. fan doesn't turn on. I bypassed the switch (jumped) and she worked. Does this mean I need to replace this switch? Can I put a jumper wire in there permanently (read somewhere that if the fan always runs with the A/C on it cools better. Thanks for your advice.
Chuck

Hi. Thanks for your advice. The whole problem was bad contacts in the switch (the one on the refridgerant pipe on the right side). As soon as I started to pull it off, the fan turned on -- the movement rubbed the crud off the contacts, I suppose. So I cleaned the contacts, used a little TV Tuner spray, and put some conductive grease on them, and reconnected the plug. All is fine, now. I guess, being so low down (it was quite a reach), some road spray is to be expected -- I hope my treatment will forestall a repeat.
Thanks again.