No Aux fan with A/C or by temp....can I swap ABS relay to test?

So today I almost overheated my 96 XJ in traffic b/c my aux fan doesn't work apparently.
The A/C kicks on but the fan does not.
I have jumped from the bat to the fan and the fan works.
I"m thinking it's either the sending unit on the thermostat or the aux fan Relay in the PDC.

I have a spare ABS relay I pulled from the PDC when I deleted it for an 8.25
.
I would like to test the aux fan relay by swapping a known to work ABS relay in.
The relay that is in the fan slot has different numbers than all the other relays. It looks like a replaced relay from somewhere by the previous owner.

My question is are all the relays the same i.e. can I stick the ABS relay in in place of the original fan relay, or will I damage something??
I thought they were all interchangeable but this differently numbered relay stumped me. The pins are even numbered differently i.e. 1,2,3 etc. vs. 85.86.87 etc.,

Can I swap the ABS relay in to test safely?
I have to fix this before driving all day for work in 95+ heat lol.
Thanks all!

The sensor on the thermostat housing sends coolant temp data to the PCM that turns the efan on when temps reach ~218*.

You can use any Bosch-type 5 pin automotive relay that will plug into the socket in the PDC to test . You can use the A/C relay if the ABS won't plug in but I am pretty sure that the ABS will work. The part nos. on the relay covers are meaningless, you just need a relay with ~30 amp capacity.

I would guess that it is quite possible you have other cooling problems if you overheated in traffic. What is status of the clutch on the mechanical fan?

The sensor on the thermostat housing sends coolant temp data to the PCM that turns the efan on when temps reach ~218*.

You can use any Bosch-type 5 pin automotive relay that will plug into the socket in the PDC to test . You can use the A/C relay if the ABS won't plug in but I am pretty sure that the ABS will work. The part nos. on the relay covers are meaningless, you just need a relay with ~30 amp capacity.

I would guess that it is quite possible you have other cooling problems if you overheated in traffic. What is status of the clutch on the mechanical fan?

2 year old 2 core copper brass GDF (??) radiator, ZJ mechanical fan.
50/50 beautiful green antifreeze. Flushed thoroughly last year. Nothing came out. Also an HD oversized tranny cooler.

I haven't changed the thermo in a while but I've verified it functions well. Hose gets hot when it opens.
It was 104 today. The Jeep has NEVER run this hot before. We were also on hot fresh asphalt jammed up waiting for construction for 15 minutes surrounded by semis.
Normally, It gets up to 218, the fan kicks on and it's back to 190.
Not so today.

so it's okay to use the ABS relay then? Cool.
I'll report back with results!

WTF??? The relay works. It did when I pulled it a while back.

Does the fan ALWAYS kick on when A/C is selected?
Or is it only when engine temps are warm?
It's cool now and I started it up, turned on the A/C.
The compressor kicks on but not the fan.

I don't get it...........

I should mention that the original relay, when pulled, was oxidized pretty good on 3 of 5 pins. I assume these were the connections running power.
Is it possible the female ports in the relay slots aren't making proper contact. How would I fix that?

Still want to know if the fan Always runs with the A/c regardless of engine temp.
???
Thanks again ya'll, and thank you Pelican for your info. PS, also a new water pump in spring.

On later models they changed it so that fan does not automatically kick on with A/C. I am not absolutely sure what year but I believe '98 or later. AFAIK your '96 efan should kick on with A/C but can't absolutely swear to it.

Good point about oxidation. Some years ago I went through similar situation with fuel pump relays, swapped in new and known working units with no joy. Finally just before I went nuts, I put a dab of Ox-Gard on each relay terminal, plugged it in and it fired up and has worked ever since. I've never pulled that relay since.

I would not normally consider that to be a "fix" but it either was in this case or I finally just got lucky.... Ox-Gard is available in electrical sections of hardware stores and the big box stores if you don't happen to already have some or similar. Ideally of course it would be good to use some kind of thin abrasive to clean the female contacts, perhaps some fine sandpaper.

It's not all that late here but I'm getting really punchy. Hopefully someone will chime in. Let us know how it goes.

Edit: I will add that Ox-Gard is useful for just this situation. Has slight abrasion characteristics and is a conductor. I always keep a tube around. Good luck.

Jumper the load terminals of the relay receptacle. If the fan turns on, troubleshoot the control side of the relay receptacle.

Awesome, Hypoid!
One catch: I'm basically electrically inept. How would I go about doing that?

I've only just recently started learning about electrical but would like to deal with this myself and learn something in the process.

I'm lost.
I can feel the relay click when I turn on the defrost or A/C but the fan does not come on.
I unplugged the temp sender on the thermostat housing while the engine was running and the fan did not come on, though a CEL did.
BTW does that mean the Sender is NOT faulty??????
.
I've jumped the battery to the fan and the fan works.

I've been bashing my brain all night hasta and I think, at this point. that I'm too frazzled to find the vector.

Had to take the day off work to fix it.

Can someone help me understand what the problem is please?

If the relay clicks and the fan doesn't come on, you have three possibilities: 1) no continuity between relay's output and the fan (broken wire) 2) fan's ground circuit is bad (again, broken wire) and 3) bad fan motor.
You may have to get creative, but if you have a voltmeter you can measure all of these things with a DMM. Get on Youtube and learn up - it will come in handy!

I've started with resistance/continuity testing the wires.
I have infinity at all the relay's terminal ports in the PDC, EXCEPT #2/86
On pin 2 or 86 of the relay's port I get about 2k ohms from the port to a good ground.
does that mean anything?

If not, where does the ground for the fan connector terminate on the chassis so I can test the wire en to end??

i feel like I'm in over my head but I'm GONNA figure this out.:repair:

Unplug the fan connector and check ohms between the ground terminal in the connector and any good ground on the body or engine. You do not need to check the wire itself end to end.

Next check ohms between the positive terminal in the connector and the 87 terminal in the relay socket. (this is normal wiring but you might as well also check between positive and relay terminal 30.)

Let us know what you find. Both of these should be essentially 0 ohms.

It's pin 85 not 86 I get 2k ohms from. oops!

I'll go check th ewires an socke as recommended.
Thanks guys. I'm making progress!





Edit" code I got came from my dumb a$$ forgetting to put the relay back in. face palm)

I"m getting 0 ohms on both spots assuming black is ground lol.
Getting infinity from positive connector to relay socket 30

???????

And you cleaned the relay socket contacts and tried at least two relays.

I'm thinking, maybe someone else will think along.

Have you checked for 12 volts at relay terminal 30 (and 87) with engine running and A/C on? Take Care!

You checked the 20a fuse in the PDC?

Lets start over on post 16 that I tried to edit:

You should have 12 volts at relay terminal 30 (with or without engine running). On the '93 this is controlled by a 20amp minifuse right next to the relay.

I get nothing at 30 with engine off. I'm using an analog MM set to 50 DC then 10 DC fwiw.

That's looks like your problem but why now all of a sudden. You checked the fuse?

I've never had the panel out of the PDC but I take it that it's not difficult. Unless someone has a bright idea, that is what I would do. I'm going to replace cables soon so guess I'd better learn.

Keep us posted. There's always hope that someone will come up with a magical solution.