a/c compressor relay

Let me know , when you put the relay back in, if it continues to blow. I have one more idea ...

 

i checked the fuse box connection (at relay) to a/c amp. with on no ground detected would love to take out the amp. and see what it looked and smells like but where is it? will check if + when off

 

I'm thinking the surge suppressor diode on the magnetic clutch has failed, and the high voltage surge from the clutch is finding a ground path through the relay coil and frying it.

http://www.customtacos.com/tech.old.../06toyrm/06toypdf/06rmsrc/rm2006ta/046000.pdf

 

AC System diagram 01:


AC System Diagram 02:


AC Amplifier location:


AC Amplifier RnR 01:


AC Amplifier RnR 02:

 

That is possible, when that field collapses it would be a big spike. Could blow the control module too--but maybe the relay coil is the failsafe?

 

Could just be luck on that end too. I'd be measuring the A/C clutch resistance, then again with the polarity reversed. If the measurement is the same, the suppressor diode is open.

 

Yup = someone beat me to it ..... I was thinking feedback from the clutch mag coil frying the coil - either needs a clamp diode (or replacement) - or possibly an intermittent ground at the compressor causing multiple spikes of inverse voltage to the coil of the relay??

 

Hi all just got the a/c amp. fri.( was back ordered ) then things got more weird, after install i tested circuit at mg. relay in fuse box looked good but didn't want to blow the new relay so replaced it with one i thought got blowed earlier< it worked !! yea nope 10 min. into test drive a/c button starts flashing got back put in new one same thing happened more testing and head scratching went to bed got up this morning plug in old relay, works I'm done will take to Toyota, will let all know what they tell me

 

Well, if it is the diode the prints show it to be in the Mag Clutch. Therefore they may want to change the Clutch assy ($$?). You could try one more thing - put a diode on the output of the relay (Striped side to wire side) and ground the other. Cost would be minor +cost of another relay if this fails ......

 

Change the compressor

 

I'm thinking the relay has a failsafe when it heats up too much it shuts down, works again when it cools off

 

first I really don't think so ..... Try to cross the number on the relay on the web and check specs.

2nd - why would the relay heat up??

 

1. I get 115 ohms on the meter between coil poles 2. don't know what's happening wish I did but after 10 min. of driving relay kicks out after awhile it works again ,get no ohms when it shuts down. the original relay is toast but have 2 others when one shuts down i can quickly plug in the other and it will work for ten min. just found that out yesterday afternoon never thought to retest them until then thought they were just blown I've messed with a lot of electrical problems over the years seen some stuff as service manager/tech at the dealership but i guess i'm not smart enough no more

 

Can you post the relay info number and I'll do some checking .....

 

$35 90987-02028 Relay

90987-02028 part number from toyota

 

http://densoautoparts.com/sites/default/files/tech-tips/Tech Tips_012_AC Clutch Inoperative.pdf
Still looking

 

No. Relays do not work that way.

 

thanks canufixit i had to get it fixed as was going out of town took it to toyota before got your info on relay they said it was the comp. and didn't have time to do it myself (to work recover,home replace,to work evac.&charge) so $1,250 later just got home fri. had to replace u-joints and carrier brg on sat. and looked at fuse box yep new relay #

$35 90987-02028 Relay

90987-02028 ( the one in the tsb) that they did not list on my invoice so they took my new relay out and put the updated one in , which could have fixed the problem with out needing a comp. got your info a day late to know for sure but a big hats off to you for such insight and help

 

Most Welcome. Sorry to hear about the Driveshaft. Hopefully you and enjoy your ride for years to come problem free....

 

I have a new theory for you which does validate the Dealers diagnosis and repair.

Turn on AC and it runs for ten minutes.

Then the compressor starts to heat up drag and partially seize.

This is triggering the fault via the revolution sensor at the clutch.

This would cause the magnetic clutch relay to turn off making you think that the relay is blown.

A standard auto relay does not have any type of circuit protection built in. The Clutch relay is only a standard auto relay. End result IMO the dealer made a correct diagnosis and repair, the relay was probably swapped during the troubleshooting phase.