Poltergeist Jeep - repair or replace

Back story:

My 1998 Jeep Grand Cherokee (I6, 4wd selectrac) has lead a rough life. She was a rental car in the midwest for several years before moving into civilian life. I bought her (cash) when I lived in MN and used her as my winter beater and conveyance to the ski slopes. She’s had a busted check valve in her fuel pump since before I bought her.



She towed the largest trailer u-haul has to offer from MN to FL in a snow storm and held her own.



Now she’s my weekend tow vehicle, hauling our boat (2klbs w/ trailer) over 30 miles of highway every other weekend.



Problem:

With 150k miles, she’s starting to show her age. Mechanical repairs do not worry me. It’s the electrical ones that have me thinking about putting her out to pasture:

1. When towing, making a moderately hard turn, or just looking at her askance, the interior lights turn on. Sometimes they won’t go off. I’ve had to install a battery cut off.

2. The hatch window only opens some of the time (it has an electrically actuated release)

3. Last week her voltage meeter kept jumping for the max reading. It would sit there for a while and then return to normal

4. Her speedometer has just started jumping wildly up and down while traveling at a constant speed. This is very intermittent.

5. Yesterday the AC vent selection system (also electrical, why?) began to switch itself into defrost. To reset it you have to manually put it into defrost and then back into recirculate.



I think that replacing the badly corroded rear hatch would solve items 1 and 2. The cost of fixing items 3-5 (and the continual 15-17mpg towing) make me wonder: should I get a new tow vehicle? My wife and I have reliable commuter cars. This vehicle just needs to be able to tow 3500lbs up very slick boat ramps while carrying two adults, two dogs, and eventually two kids.



Other than the electrical issue, the Jeep is perfect. I’ve added air springs (myself) so she tows like a champ. The drivetrain is rock solid. She never slips on the boat ramp, unlike all the SUVs I see out there. She seats 5 comfortably with room for gear or dogs in the back. If the cost of repairs is under $2k or so, I could see keeping her for another 100k miles.

If it were me, I’d get #3 checked out, all the other stuff I’d live with. Since it’s not your primary vehicle, I’d just live with it. I wouldn’t bother getting another tow vehicle since this one suits your needs, has a solid drivetrain and you didn’t mention any safety issues.