Rebuilding my 1988 Honda Accord LXI. Purchased it new and there are enough items that require maintenance.

The gages:

The temp gage recently started to jump to the top when the vehicle was cold. I did a resistance test on the sending unit and a test on the gage per the shop manual and they appear to be operating properly. The fact that the sending unit resistance reading was low and the gage was peaked at the top means something isn’t right. I reset the ECU and the gage went halfway instead of all the way when the engine is cold. In both cases the gage did move up as the engine warmed but the reading is obviously suspect. I did have the radiator replaced about 14 months ago at the local garage because I was out of town for a while and it was expedient to do that. Not sure they properly bled the system and I will do that this weekend and reset the computer to see if that makes a difference.

The fans:

I monitored the coolant temp at the radiator, don't have a thermal reader available and a temp probe in the radiator was my only option. The main cooling fan did not engage at 200 dez. I haven't checked the switches yet but the fans both work.

Two other items of note. The alternator went bad and my daughter got a jump from her boyfriend when the battery died about 18 months ago. He inadvertently touched the jumper cables together long enough for the cooling fans to run (engine was cold so they shouldn't have started). After turning the car off and restarting the problem appeared to be reset and there didn't appear to be a problem until recently. These problems didn’t seem to appear until after the alternator was replaced but that may only be coincidence. What problems if any could this have caused in the electronics? I have since replaced the alternator with a Honda remanufactured part purchased from the dealer.

Any help is greatly appreciated.

 

Jumper the fan switch to run the fans. That verifies that all the wiring, fuse, & relay is OK. The only thing left is the switch.

Reseting the computer isn't going to do anything. I don't believe in '88 that's in any way involved in the dashboard gauge, or fan circuit. The dashboard gauge sender is not the same as the temperature sensor for the ECU, they don't share information.

I'd look for a short to ground in the circuit from the sender to the dash gauge. On my cars (newer than yours) if you short the wire to ground to test the dashboard temperature gauge, you have to be careful NOT to let the gauge peg at the top. That supposedly fries the gauge. If your wire has a short to ground, you may have already done that...

 

did u replace the temp probe
i had an 89 with a cooling problem it was a bitch, now after a new head and a new engine it still died on me and now i have a new honda
goodluck

 

Thanks for the feedback. I tested the dash guage by the procedures in the shop manual and it passes all the tests so it probably isn't fried. I've also jumped all the fans and they work OK. I'll probably replace all the relays. Car's been in the garage most of the winter cause it's been too cold to work on it.

I'm also told that if you don't bleed the engine block when replaceing the coolant with the bleeder next to the temp switch you can have problems. Since this all started after I had the car in to replace the radiator I'm wondering if that wasn't the start of the dash guage problem. The same shop also replaced the oil pump and didn't put the oil pan gasket on properly so that's leaking all over the place too. Just another example of why you should to do your own work unless you find a shop that knows what in the heck they are doing.