Jeep Cherokee problem HELP

NYSpeed Automotive
1

This thing hasn’t given me any problems since I bought it. But of course, as soon as I want to sell it… F.

Anyway, it seems to be having some odd electrical problems. As I drive, the voltage surges and maxes out. Everything gets brighter, turn signals blink faster, etc. But ONLY while driving. If I sit idle and in park, no issues. Whether I rev it or not.

I took it to advanced auto to test the alternator/battery and everything checked out okay. However, that test is done with the car in park.

I already took apart the major connections to clean them up and inspected the wires but that doesn’t seem like it would be the issue. Could it still be the alternator even though it’s not giving me any problems in drive?

Any help/suggestions are appreciated.

2

Not sure if it’s the same with cherokees as grand cherokees, but the ECM will get retarded which is controlling alternator output, in addition to the alternator itself and sporadically do dumb shit like you’re describing. I didn’t diagnose any of the above, but running a shop, we swapped a few used PCM’s with some older jeeps with similar issues.

3

^I know voltage is controlled by the ecm so that sounds like it could be it. What year is your heep?

Not too sure, best bet is to check out Naxja.org

4

Shit, forgot to list vehicle details.

2000 Jeep Cherokee.
4L I6 Auto.

ECM can probably be had cheap at a yard, no? I’ll do some more digging before it comes to that, though.

5

definitely, but it’s good to know all variables involved when troubleshooting.

6

I’ll ask a buddy of mine he knows these fairly well.

On a side note you dont have very good luck lately lol.

7

A friend of mine had the same issue, this is what I sent him:

http://www.jeepforum.com/forum/f13/voltage-regulator-1240417/

He just wired in an aux reg and did not need the resistor.