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Chris
Chris, Shop Foreman
Category: Jeep
Satisfied Customers: 3204
Experience:  Jeep Certified Master Tech
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2000 Cherokee 4.0, have been trouble shooting no crank

Customer Question

2000 Cherokee 4.0, have been trouble shooting no crank issue, relay is clicking but no voltage at solenoid, jumped wire from relay output to solenoid and it starts. Isolated solenoid wire (brown) and has continuity, is there something inline between relay and solenoid on that brown wire that would interrupt the 12v?
Submitted: 1 year ago.
Category: Jeep
Expert:  bill replied 1 year ago.

do you have the vin so I can pull the correct wiring diagram for your jeep?

there are 2 fuses in the starter relay circuit and I need to pull the diagram to determine which they are

Customer: replied 1 year ago.
I don't door plate says 1999
Expert:  bill replied 1 year ago.

I need the vin to be sure you and I have the same vehicle, AND all our wiring diagrams are vin specific the vin will also be on the door plate

Expert:  bill replied 1 year ago.

do you have a test light and are you near the jeep?

I need you to test for power at the relay

Customer: replied 1 year ago.
Not near the car now, but can assure you the relay has power as it is currently starting the car when key is turned, via jumper wire from proper pin to solenoid, the question is.. Is there something inline between relay and solenoid connection that would prevent start ie PCM signal of fuse
Expert:  bill replied 1 year ago.

if the relay is clicking the pcm and ignition switch are providing power to the COIL PORTION of the starter, which DOES NOT MEAN there is power at the LOAD side of the relay, remember any relay has 2 circuits 1 for the coil that energizes the relay and closes the contacts and 1 for the CONTACT or LOAD side, so if you provide power to the brown wire on the relay which is 1/2 of the load circuit have you tested for power at the OTHER side of the load circuit, do you know how to properly test a Bosch style 5 pin relay?

I can provide instruction if needed, BUT remember there are 2 fuses on the circuit have you checked BOTH fuses?

without the vin I cannot say for sure the fuse numbers

and we have some confusion now as well you have the jeep listed as a 2000 but you also say the door plate says 1999 so I will definitely need the vin to properly get the correct diagrams, as from year to year we did change the fuses slightly and their locations

Customer: replied 1 year ago.
I have tested for power on relay, once coil is activated it closes and transfers 12v to the pin with the brown wire going to solenoid. Was not seeing the 12v on other end of brown wire, so I put in jumper from activated pin of relay via turning the key to solenoid connection and it starts? Is there a way to check just the circuit between starter relay to solenoid on both years?
Expert:  bill replied 1 year ago.

there are 2 fuses here one for the coil side and 1 for the load side THEY DO NOT INTERACT WITH EACH OTHER, on the starter circuit the coil of the relay is protected by it's OWN FUSE and the load HAS IT"S OWN fuse, so on the relay you will see some numbers 30, 85, MAYBE 85a, 86 and 85 pins 86 and 85 are the coil and NOY CONNECTED TO pins 30 OR 85 (a) pin 30 is a power to the load (your starter) and needs constant power this is the pin I need you to look at REMEMBER ALL RELAYS need 2 sources of power does your relay have 2 power sources?

look through this article and it will give you an excellent explanation of the way a relay works, you have a slight misunderstanding of how the starter circuit works.

http://www.hotrod.com/how-to/interior-electrical/1106rc-basic-electrical-relays/

Expert:  bill replied 1 year ago.

have you swapped relays with another just to rule out a bad relay?

Customer: replied 1 year ago.
I understand relays and mine has 2 12v inputs one to close the circuit and one to energize said closed circuit so is there a inline fuse and or communication with a component that would negate said 12v input to solenoid?
Customer: replied 1 year ago.
Have swapped as well
Customer: replied 1 year ago.
Are you mad at me?
Customer: replied 1 year ago.
Power on load side of relay confimed via current jumper set up from load side of relay direct to solenoid input screw
Expert:  bill replied 1 year ago.

no not mad but 99.9% of our customers have difficulty understanding electrical, and for the short time I taught automotive before getting back into the dealership life teaching relays was the 1 thing that stonewalled nearly every student.

Customer: replied 1 year ago.
As I tested continuity on brown solenoid wire I did not ohm for possible break down and or decay but find it hard to believe that would be the problem. Is there something I might be missing?
Expert:  bill replied 1 year ago.

so basic relay operation would have to say if you have power at pin 30 which is the feed to the starter on the relay contact and transfers power to pin 87 which is the starter solenoid wire (brown) NAD you are 100% sure the STARTER relay is clicking by putting your hand on it while someone cycles the key , which would mean the coil side of the relay is operating then you have a bad starter relay.

now since I am not there lets start at the beginning I would bet you're hearing the ASD or FUEL PUMP relay clicking, so I would go to the starter relay and with a test light and an assistant check for power in crank and then switch the test light to test for ground at the other pins

Customer: replied 1 year ago.
to answer my question about there being anything between load side of relay brown wire and solenoid connection your answer is? 1999 or 2000
Expert:  bill replied 1 year ago.
NO the ignition switch puts out 12 volts and the neutral safety switch provides the ground for the COIL side of the relay, and there is a fuse that feeds the load side of the relay battery power.here is a link to a generic 1999/2000 Cherokee starter circuit I CANNOT guarantee it is the correct one for your jeep without the vinit is in word format please download it and print or save it for reference as it will be available only for few days