Relay problems

Tiny
DSW422
  • MEMBER
  • 1995 ISUZU RODEO
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 120,101 MILES
OK. My 95 rodeo ls v6 automatic has been having problems for a while. This time, my relay. Specifically my fuel pump relay. When I drive, the relay gets really hot and turns off I guess, which turns off the fuel pump. All I usually do is switch the relay with another and it works, but sometimes it is stubborn and wont turn on. Eventually I find a relay that works. But it happens all the time. What could be the problem?
Monday, May 16th, 2011 AT 9:08 PM

9 Replies

Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
The relay is known to fail intermittently due to bad soldered joints. Resoldering the joints should solve the problem.
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Monday, May 16th, 2011 AT 9:12 PM
Tiny
DSW422
  • MEMBER
  • 24 POSTS
Which joints? In the relay, or in the wiring in the relay box?
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Monday, May 16th, 2011 AT 9:25 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
The relay itself.
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Tuesday, May 17th, 2011 AT 11:08 AM
Tiny
DSW422
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  • 24 POSTS
So should I replace the relay then, b/c I canot seem to take the shell off to resolder the joints. If I do have to replace it, then do I have to replace all the relays, b/c when I switch the replays, they too shut off also. I kno it is kinda confusing, im baffled to as to why it does it. Thanks for all the help.
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Tuesday, May 17th, 2011 AT 2:33 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
If switching the relays cause them to shut off, is it the one being shifted to shutting off or only the fuel pump circuit? If only the fuel pump circuit is shutting off, then you do not have any fault with the relays but a problem with the fuel pump or its circuit.
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Tuesday, May 17th, 2011 AT 8:45 PM
Tiny
DSW422
  • MEMBER
  • 24 POSTS
Ok. Then im sure that the relay is fine, and I know the pump is too since I just replaced it. So if it is the circuit, how do I go about fixing that?
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Tuesday, May 17th, 2011 AT 9:37 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
You have to check for broken wires between the fuel pump relay and pump. Usually a bad connector can cause such problem.

Remove the relay and use a fuse jumper across the terminals for the power supply and to fuel pump. If the fuel pump does not work, unplug the connector at fuel pump and use a test lamp to check for battery voltage.

Ensure there is power supply to the fuel pump relay terminals.
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Tuesday, May 17th, 2011 AT 10:51 PM
Tiny
DSW422
  • MEMBER
  • 24 POSTS
Ok. Then I guess I kno what the problem is. About 3 months ago, the very last connection for the pump didnt work. So I cut it off and connected them with crimp connectors, and put shrink tape around it. I guess that it isn't connected very well. Do you have a better way for making a connection. Thank you.
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Tuesday, May 17th, 2011 AT 11:28 PM
Tiny
KHLOW2008
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The best way is to join and solder the joints. Recheck the crip joints. Itf they are loose, disconnect them and use a plier to gently tighten the female clamps so that when the make connecter is inserted, they hold tight.

Ensure the wires crimped to the terminals are tight. If they are not, they can overheat over time as the fuel pump uses a rather high electrical load when it is operating.
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Wednesday, May 18th, 2011 AT 1:03 PM

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