1995 XJ12 No Heat!!

01-05-2004, 11:41 AM
I have a 95 xj12 without heat.
I've replaced both engine thermostats. (both were bad)
I've tested the Valve with 12v and can hear it clicking,
I've tested the water pump with 12v and can hear it running.
I've change the pump relay with a known good one.
There are no codes in the climate control system, nor in the ECU.
With the engine running and the coolant up to temp, I'm not seeing
12v at the pump nor at the valve.
With the fan set to max, front window defrost and temp set to HI,
I'm getting COLD air. The hoses to/from the heater core are COLD.

Anyone have any hints at were to start looking??

is there anyway to default the system into a heat on state?


01-05-2004, 01:32 PM
have you tried taking of both hoses to see if you have circulation through pipes/heater core?quite possible an air lock!!

10-09-2004, 01:11 AM
Greetings CLUELESS, allow me to offer you a clue in the form of a 'mental snack'.
Years ago, 1974-ish, I was in the military returning to Base from Long Island driving a 1967 Plymouth Fury. It was the fastest car ( actually it was a wagon) that I have ever owned to this day. It was the middle of winter and guess what? Thaat's right! NOO..HEAT!
Well, there was ice built up on the floor, my boot kept slipping, the gas pedal iced up to a fast idle and stopping was VERY exciting! There are TOLL booths at bridges and tunnels there in NY & NJ, so I had several reasons get some HEAT.
SO, I stopped at a SONOCO gas station to ponder this. Like yours, the heater hoses were cold. I removed one hose from the firewall and VIOLA!...RUST BIG TIME. A flushing operation was needed here and there was FREE air and water there. No fear, I found a wheel air stem laying on the ground, back then you could dial the pressure you want with a crank on the dispenser. So I inserted the stem in the air chuck, dialed 15 pounds, pushed it in the heater hose and got "liquid engine block" (rust), coming out of the tube at the firewall. And after this, I drained the radiator and BLA-BLA-BLA, got enough heat that when I reached Maryland, the carpet was bone DRY!
BOY, I sure took the scienic route to mention maybe your heater core is blocked. So 'MAN THE GARDEN HOSE MATE'!....maybe you'll be surprised! GOOD KUCK..I'll watch postings.

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