1994 Jimmy Dash and Heat problems

[djtroz]

I just bought this truck last week and found the heat is not all that hot and the digital dash has issues. I have been online for the past couple days researching the issues and seem these are common problems. From what I read, it seems the heating problem is caused by a faulty heater control valve or heater core. Before I go and rip out the core, is there a way to manually check the valve to see if the vacuum is the problem? Also, I was considering picking up a Prestone backflush kit from the autopart store. This has worked well with other vehicles, but never had a problem with heat before. If the core is just clogged, would this work?

Next, with the dash, most people are having problems with the all dash instuments going out. With mine, the speedometer, odometer and blinkers work, but the fuel, temp and charge dont light up. Any help is apprciated.
Thanks

[Killrnails]

Well, first off, I can tell you my '98 Jimmy is having the same issues w/ the heat. So far, I've had the heater core flushed twice, will be 3 times as soon as I finish typing this reply. Once again, my heat isn't working, the last time I had the flush done was 1/7/06 & my heat went out last week. I do know this, it's not the heater core. The way the core is positioned in the '98 Jimmys makes it extremely hard to get to & to replace it I got a quote of $800 along with the fact my heater core wasn't bad. What happens with this particular model is the tubes that are in the heater core get plugged w/ debris from the antifreeze (is what I was told), thus no heat is disbursed. You have to get the heater core flushed a few times, me being on my third time & eventually this will solve the problem. It costs me around $60-70 each time I get this done. Living in Michigan which today is around 26 degrees w/ massive wind, unfortunately I'll have to keep getting this done until spring *sigh*. So basically, my suggestion is try the heater core flush a few times & see what happens. No dash problems for me, yet.

~Sue

Originally Posted by djtroz

I just bought this truck last week and found the heat is not all that hot and the digital dash has issues. I have been online for the past couple days researching the issues and seem these are common problems. From what I read, it seems the heating problem is caused by a faulty heater control valve or heater core. Before I go and rip out the core, is there a way to manually check the valve to see if the vacuum is the problem? Also, I was considering picking up a Prestone backflush kit from the autopart store. This has worked well with other vehicles, but never had a problem with heat before. If the core is just clogged, would this work?

Next, with the dash, most people are having problems with the all dash instuments going out. With mine, the speedometer, odometer and blinkers work, but the fuel, temp and charge dont light up. Any help is apprciated.
Thanks

[djtroz]

Well, I'll be attempting a backflush this weekend. I'm going to throw some of the radiator cleaner additive into the system in hopes that it may help a little before I backflush it. I'm also going to do a tuneup and clean out the EGR valve so that its stops running so rough. If there is still time, I'll pull the instrument cluster out and check if there are any bulbs that need to be replaced or it there is anything that is loose.

[Killrnails]

Sounds like a plan. Good luck & let me know how it works out for ya!

Originally Posted by djtroz

Well, I'll be attempting a backflush this weekend. I'm going to throw some of the radiator cleaner additive into the system in hopes that it may help a little before I backflush it. I'm also going to do a tuneup and clean out the EGR valve so that its stops running so rough. If there is still time, I'll pull the instrument cluster out and check if there are any bulbs that need to be replaced or it there is anything that is loose.