2001 vs 89 electric

gird123 · Aug 4, 2012

Recently I replaced the pcm on my 2001 and it is running much better. My dad has an 89 and said he is having electrical issues(i'm not sure what) and that he would like to replace his computer. I searched the cite and I was a little confused as to what to replace on a 1989 xj as for as the computer is concerned. Any pointers would be appreciated.

souske · Aug 4, 2012

Have you cleaned all the grounds on the 89?

87manche · Aug 4, 2012

they in no way, shape or form share anything other than some body panels.

clean the grond. Renix ECU are nearly indestructable, it's not lkely it's bad.

and the alternator is self regulating, so if it's not outputting the correct voltage, replace it.

gird123 · Aug 4, 2012

thank you.

Ecomike · Aug 5, 2012

What electrical issues is he having? Most common ones are head lights, AC blower, windshield wipers, radio.... all tied to poor quality (and design) ignition switch, head light switch and wiring from the 25 amp fuse (AC Blower) to the ignition switch. Blower switch is also weak. Newer cars use relays for the loads on the blower and head lights, the older jeeps did not, so the switches all burn out quickly. I rewired all of mine.

All the computer does is run the engine, and its only weak link is the engine-firewall-battery and sensors grounds under the hood.

BlkXJ89 · Aug 8, 2012

Ecomike said:
What electrical issues is he having? Most common ones are head lights, AC blower, windshield wipers, radio.... all tied to poor quality (and design) ignition switch, head light switch and wiring from the 25 amp fuse (AC Blower) to the ignition switch. Blower switch is also weak. Newer cars use relays for the loads on the blower and head lights, the older jeeps did not, so the switches all burn out quickly. I rewired all of mine.

All the computer does is run the engine, and its only weak link is the engine-firewall-battery and sensors grounds under the hood.

Hm, I may contact you about rewiring the jeep. Currently none of my 89s electrical system works even after replacing the main ground and power wires.

87manche · Aug 9, 2012

BlkXJ89 said:
Hm, I may contact you about rewiring the jeep. Currently none of my 89s electrical system works even after replacing the main ground and power wires.

check the top orange wires on the firewall connector for th fuse block. Those two are responsible for the ignition switch and everything inside the Jeep.

When they go bad and get burnt you get a dead jeep with nohting electrical working, because the ignition switch doesn't get 12V to turn on the relays and such.
Mine were super nasty and burnt, I bypassed the connector and wired them through the firewall into the back of the fuseblock with 12G wire.

2001 vs 89 electric

gird123

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souske

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87manche

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gird123

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Ecomike

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BlkXJ89

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87manche

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