Electrical problem 87 Esprit - LotusTalk

Lotusrepair · 07-08-2009, 06:14 PM

A/C clutch and radiator fans not working.

Can not get power to the a/c clutch. Tested the clutch and it works fine. The front fans also do not turn on with the panel switched to a/c. Checked the relays and they work. Checked the fuses and they are fine. Not sure where to look next? Following the wiring diagram but locating the wires and parts in the car is the problem.

Just purchased this unfinished project to add to the Lotus fleet.

TheViper · 07-08-2009, 07:03 PM

I know very little about the Esprit, but the symptoms you describe could be the Trinary switch not allowing operation due to low or high refrigerant pressures.
Michael

Quote:

Originally Posted by Lotusrepair

A/C clutch and radiator fans not working.

Can not get power to the a/c clutch. Tested the clutch and it works fine. The front fans also do not turn on with the panel switched to a/c. Checked the relays and they work. Checked the fuses and they are fine. Not sure where to look next? Following the wiring diagram but locating the wires and parts in the car is the problem.

Just purchased this unfinished project to add to the Lotus fleet.

Quicker · 07-08-2009, 07:13 PM

correct - it sounds like low pressure in the AC system is keeping the compressor from engaging (and the fans from turning on). A quick test is to short across the pressure switch contacts - if the fans come on - you have a low pressure.

Lotusrepair · 07-09-2009, 05:05 AM

Tried disconnecting and shorting the switch during the electrical gremlin chase. It did not make any difference. The signal comes from the a/c controls and then through the relays. The system is currently under vacuum awaiting freon. The thing is that I have never heard the radiator fans run. The temp has never climbed up past 90. I have only had the car for a week.
I am not sure if this is normal or part of the problem. The high speed setting on the interior fans runs on slow with just the key on and then runs the normal fast speed when the engine is running. There should be no difference in fan speed between the key just being on and engine running. It seems like a back feed or bad ground.

I think this problem has been there for some time. The person I got the car from picked it up with a broken timing belt. He never had the car working till the engine was done. I asked if he disconnected the compressor or set it to the side and he claimed it was set aside and the system left intact. On my other 4 Lotus I can find all the parts of the wiring harness. This car is taking longer to learn about.

Quicker · 07-09-2009, 05:19 AM

when you say you shorted the switch - you did the pressure switch on top of the condenser? (with the little sight bubble).

the fans normally only come on at about 95 - unless you have the AC on (and working). without the AC the center one will never come on. you can test the fans seperately by running a wire from a good 12V+ and try to energize each fan one-by-one, then start working backwards....

Lotusrepair · 07-09-2009, 08:00 AM

Yes, I did do the switch on the filter/dryer. The condenser is in front of the radiator. When I first looked at the switch I was not sure if it was a high or low pressure switch. The book referred to it as low cut off switch and I tested it in both shorted and open. Really don't want to put 3 lbs of r12 in the system to find I have to take it apart later. I own 2 recovery units, but you still loose some r12 in the process. I am trying to locate the fail failure monitor. Not sure where it is in the car. On the Elite all the fans come on when the a/c is working. I see the center fan only works with the a/c, but from what I saw on the drawing it looked like all 3 fans ran for the cooling.
It is hard to get to the otter switch to manually kick the fans on.

Quote:

Originally Posted by Quicker

when you say you shorted the switch - you did the pressure switch on top of the condenser? (with the little sight bubble).

the fans normally only come on at about 95 - unless you have the AC on (and working). without the AC the center one will never come on. you can test the fans seperately by running a wire from a good 12V+ and try to energize each fan one-by-one, then start working backwards....

Lotusrepair · 07-09-2009, 06:24 PM

Fixed........!!!!!!!!!

Pulled the radio out and went through the plug connections for the system. Made sure all the pins were fully set in the housings and tried the system. It worked. Put everything back together and the system still works. Charged the system and the results are good. Sight glass is fine. Temp is good. Pressures on the gauges are good.

Now on to the next item on the list.....

lotus4s · 07-09-2009, 06:46 PM

Good work!

Electrical problems are a PITA...

carbuff · 07-10-2009, 08:42 AM

Quote:

Originally Posted by Lotusrepair

Fixed........!!!!!!!!!

Now on to the next item on the list.....

How long is the list? If it's shorter than the length of your arm, you are good to go. Start driving and be happy.

PS All the things on your list that do not prevent enjoying a drive (like the A/C) are merely eccentricities...not problems.

07-08-2009, 06:14 PM	#1 (permalink)
Lotusrepair Registered User Join Date: Mar 2009 Posts: 41	Electrical problem 87 Esprit A/C clutch and radiator fans not working. Can not get power to the a/c clutch. Tested the clutch and it works fine. The front fans also do not turn on with the panel switched to a/c. Checked the relays and they work. Checked the fuses and they are fine. Not sure where to look next? Following the wiring diagram but locating the wires and parts in the car is the problem. Just purchased this unfinished project to add to the Lotus fleet.

07-08-2009, 07:13 PM	#3 (permalink)
Quicker 89 Esprit SE Join Date: Jan 2008 Location: Austin, TX Posts: 62	correct - it sounds like low pressure in the AC system is keeping the compressor from engaging (and the fans from turning on). A quick test is to short across the pressure switch contacts - if the fans come on - you have a low pressure. __________________ _____________ Lou Senko, Austin, TX Click to see 'Quik LS' my mean Lincoln LS Click to see 'Quiker' my Lotus Esprit SE

07-09-2009, 05:19 AM	#5 (permalink)
Quicker 89 Esprit SE Join Date: Jan 2008 Location: Austin, TX Posts: 62	when you say you shorted the switch - you did the pressure switch on top of the condenser? (with the little sight bubble). the fans normally only come on at about 95 - unless you have the AC on (and working). without the AC the center one will never come on. you can test the fans seperately by running a wire from a good 12V+ and try to energize each fan one-by-one, then start working backwards.... __________________ _____________ Lou Senko, Austin, TX Click to see 'Quik LS' my mean Lincoln LS Click to see 'Quiker' my Lotus Esprit SE

07-09-2009, 06:46 PM	#8 (permalink)
lotus4s Registered User Join Date: May 2008 Location: Florida Posts: 92	Good work! Electrical problems are a PITA... __________________ 1995 S4s Visit my website: http://sites.google.com/site/jkesprit/

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07-09-2009, 05:05 AM	#4 (permalink)
Lotusrepair Registered User Join Date: Mar 2009 Posts: 41	Tried disconnecting and shorting the switch during the electrical gremlin chase. It did not make any difference. The signal comes from the a/c controls and then through the relays. The system is currently under vacuum awaiting freon. The thing is that I have never heard the radiator fans run. The temp has never climbed up past 90. I have only had the car for a week. I am not sure if this is normal or part of the problem. The high speed setting on the interior fans runs on slow with just the key on and then runs the normal fast speed when the engine is running. There should be no difference in fan speed between the key just being on and engine running. It seems like a back feed or bad ground. I think this problem has been there for some time. The person I got the car from picked it up with a broken timing belt. He never had the car working till the engine was done. I asked if he disconnected the compressor or set it to the side and he claimed it was set aside and the system left intact. On my other 4 Lotus I can find all the parts of the wiring harness. This car is taking longer to learn about.

07-09-2009, 06:24 PM	#7 (permalink)
Lotusrepair Registered User Join Date: Mar 2009 Posts: 41	Fixed........!!!!!!!!! Pulled the radio out and went through the plug connections for the system. Made sure all the pins were fully set in the housings and tried the system. It worked. Put everything back together and the system still works. Charged the system and the results are good. Sight glass is fine. Temp is good. Pressures on the gauges are good. Now on to the next item on the list.....

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