Relay problems
05-19-2003 | 06:05 PM
#1
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Joined: Dec 2002
Posts: 14
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From: Memphis, TN
Relay problems
My mechanic suggested I ask you folks for some help. Here are the problems: The AC will not come on. The AC has freon. We replaced the #11 relay to see if that would fix the problem. It didn't. He can gound two of the pins where the relay goes in and the AC will turn on, and it's cold. He has no idea what is causing it to not work. Second problem: After he (the mechanic) messed with the relays now the car will not re- 
start immediately after it has been running. You have to let it sit an hour or two and hope it starts. Sometimes it will, sometimes it won't. I don't know if this is related to work he did or just coincidental. He wants to know which relay controls the fuel pump. I'm getting more and more frustrated especially since I am moving to Memphis, TN next month and intended on driving my 928 there from Macon, GA. Any suggestions as to what may be the problems here would be greatly appreciated! Thanks!
start immediately after it has been running. You have to let it sit an hour or two and hope it starts. Sometimes it will, sometimes it won't. I don't know if this is related to work he did or just coincidental. He wants to know which relay controls the fuel pump. I'm getting more and more frustrated especially since I am moving to Memphis, TN next month and intended on driving my 928 there from Macon, GA. Any suggestions as to what may be the problems here would be greatly appreciated! Thanks!
05-19-2003 | 06:52 PM
#2
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Joined: Mar 2002
Posts: 5,999
Likes: 286
From: Texas
Bluedog, one of the Big 3 928 suppliers (928 Specialists) has a fuse and relay diagram that can be downloaded and printed out for your car. Get a mechanic that is familiar with 928's. They are unlike any other.
05-19-2003 | 06:59 PM
#3
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Joined: Jul 2001
Posts: 70
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From: scenic Hudson Valley, NY
The '85 and '86 US cars have the same fuse/relay layout....Mine is below (click on the link); the fuses are #8 and #42 (start counting from the left) and the relay is marked XX on the top row, 4th from the right.
<a href="http://www.geocities.com/stathis60/Fuse_panel.jpg" target="_blank">http://www.geocities.com/stathis60/Fuse_panel.jpg</a>
good luck - VK
<a href="http://www.geocities.com/stathis60/Fuse_panel.jpg" target="_blank">http://www.geocities.com/stathis60/Fuse_panel.jpg</a>
good luck - VK
05-19-2003 | 07:03 PM
#5
Burning Brakes
Joined: Apr 2003
Posts: 1,058
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From: Napa, Ca
I had sort of a similar problem with the starting issue. Mine would either die while I was driving or not start after I shut the engine off (say if you stopped for lunch). Either way you couldn't get it started again. Come back to it a few hours later and it started up no problem. I replaced both the fuel pump relay and the fuel filter and have not had the problem since. I think it was the relay. I went through Devek.
05-19-2003 | 07:44 PM
#6
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Joined: Jun 2001
Posts: 6,469
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From: Acworth, GA
First - You would be much better off if you learn to fix the 928 yourself. It is easier to learn to do the work than to keep on trying to train a succession of mechanics - and a LOT cheaper!
There is no "11 relay". The device in position XI is a spike suppresor.
The power to operate the A/C compressor clutch comes thru fuse #17 to Relay X, the blower relay. If the A/C blower works, the fuse and this relay are good - if the blower doesn't work, neither will the compressor.
From the relay, power goes to the A/C switch on the dash.
From the A/C switch, power goes to the A/C control head. There is a small relay in the control head that controls the power to the compressor clutch - this relay can fail.
The power then goes to the antifreeze switch on the A/C evaporator. If the evaporator gets below freezing, the switch opens, cutting off the compressor. Remove the plastic shield at the base of the windshield under the hood (careful - it breaks easily)and find the switch near the center of the windshield. Check for 12 vdc on both connections on the switch (ignition on, A/C on, air distribution lever on). If there is power on both, everything so far is OK. If there is power on one terminal, tha freeze switch is bad. If there is no power on either, fuse #17, the fan relay or the A/C controller relay may be bad. If the blower works, but there is no power here, the controller relay is the usual suspect.
From the freeze switch, power goes back to the central power panel, and goes to both the supressor in Position XI and out to the low pressure switch on the A/C receiver/dryer forward of the radiator. From there, power goes to the ccompressor clutch.
Your A/C problem is likely to be either:
fuse #17
blower relay
A/C controller internal relay
freeze switch
The no-start problem may or may not be related to the work done. First - you didn't tell us what the problem is. "Won't start" can mean that the starter doesn't work, or that the starter works but the engine won't run, etc.
Since you asked about the fuel pump relay, I will assume that the problem is that the engine spins over well, but won't run.
The fuel pump relay is in Position XX. The pump relay is functionall identical to the aux fan relay found in Position XVIII, the backup lamp relay XXII, and the horn relay XII. You may swap any of these relays for testing or to get home when one (usually the pump relay) dies.
Also wriggle and push each of the plugs on the bottom of the board to make sure that all of them are well seated.
Let us know if you need more help.
There is no "11 relay". The device in position XI is a spike suppresor.
The power to operate the A/C compressor clutch comes thru fuse #17 to Relay X, the blower relay. If the A/C blower works, the fuse and this relay are good - if the blower doesn't work, neither will the compressor.
From the relay, power goes to the A/C switch on the dash.
From the A/C switch, power goes to the A/C control head. There is a small relay in the control head that controls the power to the compressor clutch - this relay can fail.
The power then goes to the antifreeze switch on the A/C evaporator. If the evaporator gets below freezing, the switch opens, cutting off the compressor. Remove the plastic shield at the base of the windshield under the hood (careful - it breaks easily)and find the switch near the center of the windshield. Check for 12 vdc on both connections on the switch (ignition on, A/C on, air distribution lever on). If there is power on both, everything so far is OK. If there is power on one terminal, tha freeze switch is bad. If there is no power on either, fuse #17, the fan relay or the A/C controller relay may be bad. If the blower works, but there is no power here, the controller relay is the usual suspect.
From the freeze switch, power goes back to the central power panel, and goes to both the supressor in Position XI and out to the low pressure switch on the A/C receiver/dryer forward of the radiator. From there, power goes to the ccompressor clutch.
Your A/C problem is likely to be either:
fuse #17
blower relay
A/C controller internal relay
freeze switch
The no-start problem may or may not be related to the work done. First - you didn't tell us what the problem is. "Won't start" can mean that the starter doesn't work, or that the starter works but the engine won't run, etc.
Since you asked about the fuel pump relay, I will assume that the problem is that the engine spins over well, but won't run.
The fuel pump relay is in Position XX. The pump relay is functionall identical to the aux fan relay found in Position XVIII, the backup lamp relay XXII, and the horn relay XII. You may swap any of these relays for testing or to get home when one (usually the pump relay) dies.
Also wriggle and push each of the plugs on the bottom of the board to make sure that all of them are well seated.
Let us know if you need more help.
