Cooling Fan Not Working

[3X00-Modified]

How many temp senders does the quad have? you never answered that. There are sometimes 2 sensors, one for the ECU and fan and another for the dash reading... if you've replaced only the one for the dash then you are possibly missing the whole problem. But the Thermostat could also be an issue.

[uncle]

There is a coolant temp sensor and a electronic temperature sender - they were both brand new and replaced with another new set.

[Cliff8928]

Did you check that you have power at the relay? It's possible that something happened to the fusible link. You can also check that the PCM is providing a ground to the relay when the fan is being requested, like when you have the ALDL jumpered to check codes.

[uncle]

Changed the T-stat yesterday and it did nothing to help.

Cliff- I cut out the fusible link trying while trying to eliminate any possible shorts

[Cliff8928]

Have you manually jumped across the terminals with the relay unplugged?

[uncle]

No I haven't and I'm too frustrated to deal with it any longer so it's going to a shop next week to get professionally diagnosed. I'm betting on something to do with the AC system.

Thanks for the suggestions

[daguse5853z]

uh do you know how to use a multi meter?

[Cliff8928]

The A/C system does not directly control anything with the fan. In the Beretta, the only thing that is energizing the fan relay is the ECM/PCM.

[scd88ga]

Uncle, my car did this when I first got it as well. All my parts were new as well because I had just rebuilt everything. I diagnosed the problem as being a bad ECM/PCM, and yes, that was the issue! I threw in a $10 salvage yard ECM and now my Quad Z26 stays cool on hot Summer days!

[uncle]

I need to get the AC charged, tire repaired and a front end alignment regardless - so I am going to have them take over from here. If it is the ECM, does anyone have a spare to keep on standby for me?

[scd88ga]

I need to get the AC charged, tire repaired and a front end alignment regardless - so I am going to have them take over from here. If it is the ECM, does anyone have a spare to keep on standby for me?

If I had one I'd just send it to you for free, but I do not. I'd ask speedy maybe or draftin

[uncle]

Well, evidently I never let it warm up all the way because I was concerned about the temperature and that the gauge was spiked - The shop called and said the fan does come on when warmed up all the way. Is it still the ECU or is the cluster fucked ?

[SuzukiGhostRider]

I have a thermostat that I am going to install next - It sat for about three months so maybe it could have froze up.

The AC does engage but it isn't charged, as getting it running is priority over staying cool while driving.......... Would lack of refrigerant (I replaced the entire system) cause this?

Yes.

Sounds to me like a T stat being stuck. Temp on the back sensor spikes, yet the one up near the T stat doesn't get hot enough to trigger the fan.

Not how it works on a Quad at all. Temp sender and Temp sensor are RIGHT NEXT to each other on the firewall side of the T-stat housing. Like literally an INCH apart. So gauge feed and ECM feed sit at almost exactly the same point on the t-stat housing.

Yes, Jon, pulling the CTS sensor plug will almost immediately kick the fan on by ECM default. It's a fail safe. The same EXACT thing should occur when pulling the TPS plug. Also a fail safe.

If your fan is not coming on when the A/C is put on Max, but the clutch on the compressor is engaging, then it's likely got JUST enough refrigerant to kick the compressor. Which, unfortunately is NOT enough to kick the pressure switch that runs the fan when it senses a high enough pressure from refrigerant in the line.

Sounds to me like the good old standby. CTS (Coolant Temp SENSOR, not Sender). In my case it was a bad CTS pigtail which can be bought NEW on RA, at O'reilly's and a few other places.

Have you direct run the fan with a few test leads to the battery yet? If you do that and it powers right up, you KNOW you have a bad CTS, bad CTS pigtail, bad relay or a bad ecm. 99.99 times out of 100 it's the first three.

Btw, in case you don't already know this, the neck on the t-stat housing for Quad's where the CTS and CT Sender are located is part of a bypass fed by a notch in the head. So , in other words your t-stat could stick all day long, the ECM would still know via the CTS that the car was hot enough for the fan to be kicked on.

[scd88ga]

I know of 4 people in the past year with quads (including myself) that had issues like this that ended up being a bad ecm! That's a pretty high number for being a .01% chance... Just saying

[SuzukiGhostRider]

Anything you WON'T say to start crap lately?